We've created a number of custom steps for Workflow Manager using your sample in C#. The code can build fine and the assembly is registered, but when unregistered it fails. The code for registration is:
static void Reg(string regKey)
static void Unreg(string regKey)
The error is:
I've looked in the Registry and the class id does exists, but I can see the "Implemented Categories" is not there. Shouldn't there be a "JTX Custom Steps" category for this in the registry?
Any help would be greatly appreciated!