F1 to H1B

I graduated from my masters in fall 07, currently i am on my OPT taking non matriculate courses that will be waived off from my PhD which i wish to start from fall 08 whle i am working with my current company. My H1B has been approved recently and starts 1Oct 08. However I have been told by the university that i cannot enroll in a degree while on OPT(session starting sept 2nd) and that I would need to be issued a new I-20 for fall 08 session. I have also been told that the visa change would not happen during the course of the semester. But if that does not happen my H1B will get canceled and I will have to be on F1 therefore not able to work with my company anymore. Please suggest if this is correct, if yes, is there a way to get around this situation