Change 'Save As' to use part number sequence instead of adding Copy Of in the part number field?

With Aras V11, SP15:

For the Part Item type, we have a pattern setup that we want all parts to follow this pattern: PRT-##### and we want it restricted to this length (9). This works. 

However, when someone does a 'Save AS' or in an Express ECO chooses to renumber a part.  we get this error "The given value of type String from the data source cannot be converted to type nvarchar of the specified target column." 

This is because we've set the item_number length to equal 9 and Aras is trying to create a new part with the number field set "Copy of PRT-#####".   We can get past the error by setting the item_number length to 20 but we don't want to do this as people can then create parts that don't match our pattern.

Where can we change it so Aras doesn't add the "Copy of" in front of the original part's number:

We'd also ideally like it to just grab the next number in our part number sequence.

I've been hunting through aras methods but can't find where the "Copy of" is being added. 

Anyone know?

Thanks.