Thanks, Lukasz.
That's another (one?) reason for upgrading to the later version.
I tried it in WF4 and couldn't work out a way to use the 'PTC_CONSTRAINT_SET' parameter.
It would let me make the column in the model tree, but, when I tried to modify the value, it told me 'the name is reserved'.
I tried creating a random parameter and making it equal to 'PTC_CONSTRAINT_SET' with a relation, but it didn't like that either.
So, in WF4, it's there, but only to tease us. We have to wait until CP2 to be able to use it.
That sounds like a really significant new functionality.
Well done, PTC.
Cheers,
John