Mine is the Bintel one also.
I found the barlow to bottom out too early in the SW adapter and I wasn't able to achieve focus in anything, eyepieces or the DSLR.
I used a parfocal ring and mounted it on the barlow element and used it without the SW 2" adapter and it worked fine.
Here is my thread on it when I was trying to figure out what was happening, It might help you picture what I'm talking about easier...
http://www.iceinspace.com.au/forum/s...d.php?t=107743