Apparently I can't do park adjustments

I know people have various different methods of doing park adjustments, but I cannot for the life of me figure them out. I attempted to reconcile various different numbers from 2008 on FanGraphs, when they published their park factors for the '08 season, to no success.

So I humbly posit this simple question to my fine colleagues here in hopes of an answer (and no ridicule, I hope). I have the following inputs:

Runs above Average (from wOBA) for a player, unadjusted for park context; Park factor adjusting runs from neutral league context to specific park; League runs/PA rate

I ask you how to calculate the park-neutral Runs above Average. My latest attempt to figure this out has come out as follows:

RAA (neutral) =(RAA (unadj) + (Leagure R/PA - (League R/PA*Park factor))) / Park Factor

With this equation, I seem to get wonky results the higher the unadj. runs above average gets (similar the lower it gets). Also, calculations with a negative RAA (unadj.) using this equation don't make intuitive sense to me, though they do correct in the general direction. Am I missing something, or am I just not hitting my calculator buttons right?