Just to help others reading this, I'll post my solution.
Exact same thing happened to me in my 18x36 Vinyl Pool. After many attempts at using the vacuum only to find the glass filling up my vac hose and not making it into the skimmer, as well as being worried about missing some, I discovered a much easier method.
Glass sinks, even little shards, so as I moved around in the water I could see the glass flowing across the bottom in waves. I decided to attach a nozzle to my garden hose and take it into the pool, shooting the water across the bottom of the pool I started at one corner of our shallow end(right where the slope drops off) and worked my way back and forth, corraling all the glass and even other debris into the front corner of the pool. it worked beautifully. I could see the glass moving and knew if it was moving the bigger pieces, then the little shards were getting moved as well.
One tip, buy a Mask, not goggles.. big difference. Mine was a cheap $7 mask from wal-mart but it worked enough to do the job. Then, once the glass is in a pile in the corner, I brought out the shop vac and sucked it up out of the pool. Get the vac hose in place in the water, above the pile, then turn on the vac. Lift the hose up from the water and point it upward before turning the vac off.
BTW, my shop-vac of choice is the RIDGID 16 Gal Blower Vac at Home depot($119). I watched a pool cleaner suck a foot of black gunk water from the bottom of our pool when we first bought the house, with this vacuum, and I said that is the one I need. It got good reviews too.. just make sure you buy the optional WET sponge filter(about $16).
I did this process twice to make sure I got it all, then I used the same method down the slope, pushing everything into a corner in the deep end, only I used my fingers and pool vac to pick up this pile, since there wasn't as much and the shop-vac couldn't reach the bottom. Then I used the brush and swept the entire pool toward the main drain, just to make sure there weren't any tiny shards in the shallow end that I somehow missed. If so, my regular vacuuming will get everything over time.
-Robert
Charlotte, NC