I think I'll try bumping this again, if it's not a problem...
I'm just kind of out of ideas here is all...
EDIT: So I figured out where the discrepancy is... since, as I said, I'm looking to do Diamond, Pearl, and Platinum, I was starting with Diamond. I assumed they were all the same in this regard... but they're not. I can see Platinum's just fine, though...
Which means Diamond and Pearl's might be impossible...? I'm not sure... but I suppose I'll keep looking for more information on Diamond and Pearl specifically. Thanks for the help so far, though, CrystalLink.
EDIT2: Once I figured out the problem, I was able to hunt down the solution. For anyone who finds this thread looking for answers later, I found said solution here: http://www.pokecommunity.com/showpost.php?p=4238206&postcount=1506 (just past the "EDIT" mark on that post)
Happy hacking.