OK, so we all know how to use a dedicated Minox flash with our Minox cameras; how about employing a non-Minox flash unit with the same cameras?
We need a flash shoe adapter, of this type here. Illustrated, a Hama hot shoe adapter:
Then, see the following advice from the good book (Marvel in Miniature – D. S. Young)
If anything else is needed, please write to me at firstname.lastname@example.org, or peruse the flash section here. All the best!