First of all, some Kenyans are a little upset with Bashir visit. (Some Gration hand behind this already?)

Kenya’s PM party distances itself from Bashir’s visit as more details emerge on trip

“We would like to point out to Kenyans and the international community that this was indeed a very unfortunate visit that could put into question the commitment of the government to implement the Constitution of the second republic in letter and spirit,” Nyong told a news conference on Saturday according to Capital FM website.
SOUTH SUDAN ANGRY AT KENYA
"Our president was all set to travel to Nairobi for the ceremony and had even sent his advance team, only to be called by President Bashir on Thursday afternoon informing him that he would be in Nairobi. Mr Kiir had no choice but to cancel his trip because protocol does not allow them to travel out of the country at the same time,” said the head of the Southern Sudan referendum campaign, John Andruga Duku.
http://sudantribune.com/spip.php?article36107

Just this resumes so well the atmosphere in Sudan. And Kenya does have a lot to loose with getting angry with South Sudan. Many of the infrastructure companies working actually in South are Kenyan (well Uganda must be happy.)
But Kenya is trying very hard to push China to fund the new Lamu port (which includes an international airport and a pipeline to Sudan oil plants). So inviting Bashir over Kiir does make sense in fact. Especially as China is officially supporting the Khartoum road to referendum. I do believe that China does make huge efforts to seduce Juba but up to now, US and UK bounds remain the most important.
Once again, we have here in fact a diplomatic war between Uganda and Kenya (with US and China behind) on who will get the oil cake market. The one who’s got the most to loose anyways is Kenya as they do not have oil, unlike Uganda. But Kenya does have “secured” boundaries with South Sudan. Last year events in Nadapal have clearly shown who the boss in town. And it’s not South Sudan who still depends on Kenya for its heavy military equipments imports.

South Sudan refutes claims that oil revenues have been paid in hard currency
The central banks governor has also refuted the south’s claims that they are running out of foreign currency. According to Hassan the Bank of Southern Sudan (BoSS) has reserves of up to US$726 million, twice the amount he says that the Central Bank possesses.
Elijah Malok Aleng, deputy governor of the Central Bank of Sudan and a governor of BoSS denied this. After a briefing with south Sudan’s president on Friday, he told South Sudan TV (SSTV) that south Sudan’s reserves were less than half what the central bank claimed.
“We only have a reserve of about US$300 million”, he said.
On Monday 23 August, Athorbe the southern finance minister told a press conference that the central bank’s action was starving the economy of southern Sudan of the hard currency it desperately needs to operate.
“The foreign exchange needed by the business community to pay for imports and to meet their foreign currency obligations and commitments cannot be provided. Investor confidence in southern Sudan is eroded as we cannot meet their foreign exchange requirements. The public is unable to send money to their families abroad for school fees or any other purpose’’, Athorbei said.
http://sudantribune.com/spip.php?article36100

So if you were wondering what economical warfare impact does have, well here is a full open air demonstration.
Not that people could afford school fees in the first place but the impact in mainly on external investors and GoSS capacities.
In juba, you can pay in Sudanese Pounds but everyone will take (and prefer) dollars. The rate last month was 2.6 SP for 1US$ while on Uganda boarder, it was 2.75 or 2.8 for 1US$. Convert that in millions… Let say $426 millions. In Sudan Pounds at Juba rate (which was at the same level than Khartoum, 2.6), it makes SP 1107 million. Now go and convert it on regional market at 2.75 rate, it makes $402 million. Immediate loss: $24 millions. Ok, that was for 2 month only. So lets replicate it for 1 year, it makes a $144 million loss. On a South Sudan budget of 1.3 to 1.5 billion/year… That does make a difference. And we are talking on the fact that 50% (approximately) of the oil revenues are paid in hard currency. So in fact it’s a loss of $144 million on $750 millions, nearly 20% of expected revenues.
On a Khartoum point of view, this is all benefits: GoSS is either buying fewer weapons or building less infrastructures. In the end it affects South Sudan stability anyways.

Cause don't forget, South is not secure yet:
Lakes state cattle keepers tell government to protect them or give them back their guns
http://sudantribune.com/spip.php?article36099