I've had limited success with this before giving up.
If anyone has a tried and tested method for this I'd like to see how they do it.
I think I had it working when the WT is created but not when it changed.
This worked perfectly - thank you so much!
Is this the funcionality that gave problems with the business rule to create new items? If so, allow me to add this information to all interested parties for future reference :-)
If we follow the steps in that KB, and have another rule to create a new item, it won't copy properly the work target when the ticket enters ou exits any state that put the WT on hold.
The workaround that Bruno and I found, was to create a new item using a template, even if all fields are set to inherit.
Hope this helps a little more.