Suzuki ts250 teardown

Hello I am having some problems breaking down my engine I have it 90% taken apart and cleaned but I'm having troubles separating the case halves. I'm doing this to check the transmission and replace the center case gasket since it leaks. I removed half of the case bolts but the other half are stuck i have an impact driver but that dosent help. I'm worried if I drill out the bolts that the studs will still be stuck and I won't be able to get them out. Any ideas these bolts don't seem to be able to take any torque. http://imgur.com/064T2n3 http://imgur.com/JqE77Am