[2005] How to duplicate project under VSS

I want to copy a complete solution to another location and make changes on it. I do not want the copied solution to be linked to source control, but the source project is linked to source control and the IDE complains about that when I load the copied project.

I find it is not enough to delete the mssccprj.sc, project.vsscc and vssver.scc files, and make the rest of the files writable. There seems to be something embedded somewhere that's linking the project to VSS.

Any ideas on the best way to do this?