OK, still have this issue from a while ago.

According to the SW documentation, the return values for successare as follows in the CustomPropertyManager methods:

Add2 = 1 if success
Delete = 0 if success
Set = 0 if success

Yet, in SW 2007 and 2008, the following values are actually true

Add2 = 1 if success
Delete = 1 if success
Set = 0 if success

So, as you can see, Delete actually returns 1 if it succeeds, not0.

Can some of you please try this out as well. I have tried it on 3machines and 2 different versions of SW
SolidworksApi macros