Lab rotations

[Java]

I came to USA for masters' and now working on OPT, I have an admit for fall 2011. I am interested in starting lab rotations even before aug. But once I do sevis transfer from current univ to new univ, then my OPT ends. For example if I do sevis transfer on june 15 then same day OPT ends and I cannot work from then at my current job, I know I can stay in USA until Aug for school to start but can I work towards my lab rotations at that time? I contacted new univ they said they cannot answer until they see my sevis info which they will not until next month or more when I plan to transfer it to them.

Anyone has any ideas on this?

thanks