saw one of these planes at my flying field last week with this same engine. That guy had used a Du-Bro 4-stroke throttle linkage to hook up his servo/throttle. The linkage itself was attached to the engine mount. This arrangement is somewhat difficult to initially set-up, but once done, seems to work great. Take a look at the website for this item:

http://www.dubro.com/Cat_2002/Cat_44.html