I recently purchased an HHKB pro 2 (feels like heaven!) but I'm running into a major problem: the lack of dedicated arrow keys. It's driving me insane!! However, I do recall hearing of "external" keyboard devices like numpads so I'm hanging onto the possibility that something like this exists for arrow keys too. Am I correct or do I have to live like this for the rest of my life 
I found it awkward at first (a couple weeks, I think), but eventually it totally became muscle memory. For some uses, like graphic design work, it's still pretty awkward -- and when I doing a lot of nudging of stuff in Illustrator or Photoshop, I tend to hook up a full-sized board, also for the dedicated F keys.
But for routine text editing use, I don't have a problem with the FN-layer arrow on HHKB at all, even when doing combos like option+arrow to move a word at a time, or option+shift+arrow to select a word at a time. My fingers now just snap to the right keys, and honestly I find that the HHKB layout means that even doing all that, I'm staying much closer to the home row. When I go back to a board with separate arrow keys, it's a further reach and feels less natural. Also a pretty big fan of the Delete key being right above the return.
All that said, if you *really* can't get deal after giving your hands a chance to get used to it, I'd agree: just get rid of it before using something as awkward as "external arrow keys". There are other Topre boards with built-in arrow keys, and you'll get great resale value out of your HHKB.
