Michael,
True, you can't change a decoder type.
Here is where the use of the 'username' comes to play. IF you have user
names on the existing signal entries and then had those used instead of the
systemName in the panel, you could:
1. create the new signal as a decoder. Leave the username blank for now.
2. Right click on the old signal and pick 'move'.
3. Select the right new systemName as created in step 1.
4. confirm the change
Repeat as needed. You will have the new real decoders working instead of
your virtual decoders.
-Ken Cameron, Member JMRI Dev Team
www.jmri.org
www.fingerlakeslivesteamers.org
www.cnymod.com
www.syracusemodelrr.org
Ken Cameron