SW Simple Macro I just can't find

[GunderSTORMIII]

I'd like to find a Solidworks Macro, that simply takes a Custom Property (in my case it's PartNo) and using the mid$ command take the last 4 characters of the property, and dump them into another Property called DetNo.

I'm at a loss trying to find the code to just simply grab a custom property to do the bolean mid$ command to it and dump it out.

I did the DIM's and I think I got all the "sets" correct, I'm just failing at the final product. I have a Library of close to 5000 parts in this assembly, all of which need have this macro run on it. Once I get the Macro, I can batch it using TaskScheduler.