[boost] [1.35] compile with vc8 the co-existence of vc8 & vc9

Hello, I have both VC8 and VC 9 installed on my machine. It's quite smooth to build with vc9. However even if I started from VC8 command line prompt and it seems to build with vc9 still, even if I use this command: " bjam -toolset=msvc-8.0 install". Is there any way to force to go with vc8?I need to build both version of lib. Thanks, Tom