Thanks FELDJAGER for the brief "tutorial" on how to adapt the MAG magazines. Just got my mags from eHobbyAsia last week, filed the ridge like you said and voilá!!! they worked just fine... Took them for a skirmish on Sunday and couldn't be happier with the result... and I must add that I did not experience any problems with the feeding so I didn't need to crack them open and do any sort of modification... There's a small wobble though, but nothing I can't live with...
Thanks again.