A 6" tube usually means a shorter overall focal length than those 8 and 10 tubes. Have a look at this 6" Bintel dob which has a Crayford style focuser, that one should fit your scope, why not ring Bintel and as them if you can source that focuser for your scope.
Alternatively, just buy a focuser that will fit your tube. Here is a base that will probably fit:
http://www.teleskop-express.de/shop/...160-205mm.html
Here is a discussion on mounting it:
http://stargazerslounge.com/topic/10...r-6-newtonian/