I am assuming the guide scope you have is designed to go into a dovetail finder bracket? If so you will find that it is quite solid enough for short focal length imaging, which if you are using a DSLR with a camera lense sjould be find. The problem is that these are designed to be mounted on a scope rather than on a bar with a Vixen attachment.
Now tell me if I am wrong but if the side by side bar looks like this
http://www.bintel.com.au/Accessories...oductview.aspx and you get a finder scope dovetail bracket like this then assuming the dovetail on your finder is the same width you should be able to attached them together. I have checked on my bits I have that are the same and it would be possible. Of course this assumes the dovetail on the guidescope is a "standard" one. WO may have made a unique design that is designed to attach to one of their scopes.
Maybe some photos may help?
Malcolm