Sorry Goran,
I read your equipment list too fast and stopped after seeing the 80 mm refractor. It ought to work fine with an 8" reflector. Just be sure you have the proper focus travel. The barlow setting relative to the CCD is not as tricky as with a reducer. On the AP barlow that I use the power changes a bit but good images are returned over quite a range of distances. You might want to consider the AP barlow as it is pretty darn good and available. The one negative that I encountered is the lack of 2" filter threads on the scope end. I needed those threads for a light pollution filter and had to build a special camera adapter as a work around. I spoke to AP about this at the expo in Tucson last year and they said there will be a new model with threads. You might want to ask if you are thinking about this one. I cannot speak about the TAK extender. It's probably also quite good but you had best check on thread sizes etc as I understand TAK can be a bit "different" in that department.
http://www.astro-physics.com/index.h...acc/visual_acc
Peter