Yes, the source code for the BeOS version is in the source code downloads.
There has been a lot of work on the BeOS version since 0.7.6, so I would
suggest grabbing the nightly CVS build, and start from there. Thomas
Fletcher and Daniel Berlin should be able to let you know where to get
started in the code.
Let me know if you need help with CVS.
Robert Sievers
Open Source Evangelist