I tried installing the freeware Synth1 ( which is a great synth)and if you delete the other DLL's in the package, ( keeping synth1.dll) and copy the files over to the unsupported folder on receptor, it actually installs!. You can see the GUI. You can click on the options screen and select where the banks are. Once you select OK, you can select the banks, and you can see the patches....BUT, once you select one, Receptor reboots.
BUT
You can change sounds on the GUI itselef and save it as a receptor patch, and you can still use Synth1 that way..so a compromise.
Just thought I would report that
TC