I would not suggest glue. Some glue will have elasticity, sure, but will eventually fall off (if not immediately) when the fabric stretches.
For my Amano Rydia tights, what I did was I made applique patches out of the same lycra and did the beading on that, then I hand-sewed the beaded patch onto the fabric. Worked really well and didn't cause any strain on the actual tights.
Animazement (NC) - Anime Festival Orlando (FL) - Holiday Matsuri (FL)
Upcoming costumes : Harle from Chrono Cross, Narciso Anasui from JoJo's Bizarre Adventure Part 6, Lina Inverse (bunny suit) from Slayers, NiGHTS from NiGHTS into Dreams...