Carry a handful of tiny eye lags (screws), and carefully place them in the edges of the platform, then tie out your guylines to them. You might need to bring some extra lines to tie out the main body of your tent in lieu of staking it. Don't forget to pack up the eye lags when you leave in the morning.

http://www.stanleyhardware.com/default.asp?TYPE=CATEGORY&CATEGORY=HDW+LAG+EYE+BOLT
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--Ken B