Well lets look at them and see if it is possible.
Beretta M92 mag. ProMag BersaHC9mmPro

This ProMag is not the exact same thing as a OEM Bersa HC9P mag.

And as I can not find any actual pictures of the Bersa HC9mmPro magazines. Even on the Eagle Imports web sight they don't have pictures.

I have a 15 inch display set to 1280x800 res.
My Bersa HC9mmPro magazines are almost the exact same size as this picture. Beretta M92 mag
They are not exactly the same but they are very very close. With some filing at the mag disconnect hole you might be able to make them work.

I bought 4 of the Bersa Factory mags for mine. I wanted to be sure they would work.
Have not found any after market mags for this pistol as of yet that are drop in replacements and this ProMag is not a drop in so far as I can tell.
And it looks like MecGar does not make mags for Bersa.

Not much but I hope it helps some how.

Found this today.
Hope it comes through.
This is a mag for a Firestorm. Basically FS an Bersa are the same guns both made by Bersa, and the mags are interchangeable.
This mag is for a FS Mini/BersaUC40 the length is different but the mag release notch it the same as my BTHC9mmPro



Note that on the Beretta and the ProMag. the notch is a slot. And while you can not tell the location between the two mags the notch on the Bersa/FS mag is higher up on the mag than it is on the Beretta/ProMag and much larger.

Thank you for such a thoughtful reply and for the photo posting work, Missouri. Based on this work I'm going to pick up a Beretta 92 mag and give it a try strictly as a range mag. Like you, I bought four factory Bersa mags just to be safe, and any work I do on the Beretta mag will be strictly for range mags I can eject onto the ground and kick around, etc. I would not carry with a modified mag. Thank you again, I sincerely appreciate it. I will be sure to let you know how it works.

JP