For those like me preferring to have the smallest portable studio has possible, There is my last finding...http://cgi.ebay.ca/Nikon-Flash-Speedlight-Strobe-Bracket-Adapter-Bowens-/190474814735?pt=LH_DefaultDomain_2&hash=item2c592f050f
This is a Bowens flash adapter where I have been able to screwed the standard hot shoes of Minolta flash on it (you can easily removed the standard hot shoe already in place). It works great and specialty this model allow you to turn the flash in the good rotation to cover the Rectangle aspect of the soft box.
Instead of buying it on Ebay, I went to the small store of the seller in Montreal West Mount area and discussed with him. He explain me that he designed it and give the instruction to one of his friend in China. He had other good stuff in the store too for good price too.
Hope this will help other people,