Download the 1.47: http://code.google.com/p/rsbuddy-api/updates/list
Rename it to .rar and open it with winrar then get the version.dat from 1.49 resources and place in the 1.47 .rar resource.
Rename to .jar and happy botting
[This guide was posted on RSBuddy's forums and I thought it would be nice to post it here to. I collected the info in some threads/replies and put it all together here.]