It is not possible to switch a project from java.net to sourceforge. Of course the code can be copied without problems. But I think it is not very usefull to create two projects with the same idea at two different locations.
I started the project because you said there is no SVN server available but I think it is very usefull to synchronize the work. Of course I will add you as project administrator to the newly created on java.net.
If you prefer Sourceforge, I will be happy to join your project there. So it is your decision
.