In the \Common Files\afx\parts\profiles folder you have a sel_list.txt file. Open it and add a new folder if needed for your parts.
Then create a folder in the same location with the name you've added to the selection list.
The easiest is to copy and existing profile and change it to represent your part. As an example go to the afx\parts\profiles\steel_beams_mm folder and copy the prt,drw,png and tab file of any item and paste it in your folder. Change the part and the tab file for the different sizes
You will also have to create a sel_list.txt file for your new folder. Use one of the others as an example. It must have your part name in it with a space and then the word part at the end.
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