MRB68 - Like some others have already said, the key is putting weight firmly on the footrest of the center stand. Your weight is your best friend in this case.

I'd humbly recommend starting with the bike on the sidestand...lift her up off the sidestand while stepping down a bit on the center stand. You'll feel it when the feet touch, and can even rock it back and forth a little to ensure both feet are touching (i.e. she's straight/vertical). Then simply step up with your full weight on that one little step on the center stand, and pull up a bit on the grab rail.

Kkromfols - I'm a little surprised your dealer would not have much knowledge of the F6b since they're essentially the same GL1800 built and sold for 15 years (minus the trunk, air ride and reverse). The GLs are pretty reliable, so I have no doubt they don't see them "often" for repairs...but I'd still expect them to be quite familiar with the model line. Just my 2 cents.