Hello Tom!
The Werke Nummer I first gave for BI+ER was wrong, typing/reading error. It has now been corrected to 14254 also on the original posting.
The MT-225 was WNr 13577 and it's Stkz DH+UQ. Note the third letter is "U" not "V"!
If you like you can contact the author of the article in Suomen ilmailuhistoriallinen lehti, mr. Pentti Manninen, at (e-mail address also given in the magazine):
inscale72production@luukku.com
AFAIK at the moment he has Stkz for all FinnAF Bf 109 G-2, save one:
MT-221, WNr 10522
If anyone can help with that, contact Pentti at address above. He has degree in history, researches, writes and publishes about Finnish aviation history and works from primary sources (as with the Stkz case here).
As far as I am concerned, I think haven't anything to add any more.
With Best Regards,
Kari