You may get a better answer on the build forge forum
(http://www.ibm.com/developerworks/forums/forum.jspa?forumID=973), but here
is what I think is possible.

Jazz SCM provides a command line tool called "scm". I believe with this, you
may be able to create a build forge source control adaptor.

There is also a plan to provide RTC support in an upcoming build forge
release, which will allow you to more easily create RTC build definitions
from build forge projects, and mirror your build forge results in RTC.