Upgrade PD 4.0 to PD 7.0

Hello,

I recently upgraded my iMac from Snow leopard to Lion and my Parallel desktop 4.0 doesn't work on Lion. I saw that the upgrade for PD 7.0 is only available from PD 5.0 and above. I was wondering if there is any way to upgrade the PD 4.0 to PD 7.0.

BTW - I recently bought the PD 7.0 to my macbook air, is there a way to use that one for the iMac.

Thanks,

Uri