I don´t know how you do it.
I usually do a drawing of the generic and then save a copy, open the copy and replace the model.
I made a small script for that, just for fun.
It works like this:
1 - Open Creo
2 - Set Working directory
3 - Open generic part
4 - Call Mapkey "FT"
This mapkey will open the Family Table window and copy the first column to the clipboard.
Then a script will create a array from the content of the clipboard.
The script opens a drawing with the same name of the generic part, saves a copy with the name of the first instance,
Opens the new drw, replaces model and save the file. Repeats for each instance.
This process may take a while if ft is big, consider taking a break for a coffee 
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Remember that the script just works if prt and drw have the same name.
Edit file header.txt, and replace the text with the first two lines of one of your trailfiles.
For creating dxf´s type call mapkey trail.
More about FT-Drawing script in:
Jose