Guinevere Trip lever/arm installation

I recently bought and installed a Guinevere (floor model). However, I can't get the trip lever installed satisfactorily. It seems like it just hangs there and isn't actually attached to the toilet and I can find no instructions for how it is supposed to be installed. The guys at the plumbing store basically told my wife that you just push the lever on the arm really hard, but it seems like the attachment on a toilet this expensive should be a bit more robust.

Thanks for any assistance

Bruce