How do I convince bjam to build multi-threaded libraries?

I'm not getting the "=mt" version of the library I'm building. When I run bjam, it just doesn't build the "-mt" versions. I *think* it did in the past, I just don't know how I convinced it to do so. A cursory look at the "getting started" page didn't reveal the answer. Do I just need to look more closely? Any pointers appreciated. Here's what I do: Download windows bjam.exe to boost directory. open command prompt. cd to libs\log\build call vcvars32.bat call ..\..\..\bjam Thanks Andrew