In effect, 2007 format IS 2010 format. In a limited sense, the primary difference between 2007 and 2010 are the design tools and GUI. There are more fundamental differences.
I have an Access 2000 database that I opened in Access 2010 saved in the default Access format on one PC and the calendar control I have in there (msocx whatever... the one that isn't supported in Access 2010) is still working after I saved it in the default format. (I went to File > Save and Publish and saved as default format). I then did this on another PC and the calendar control did not work.
How can this be? If I can force it somehow, that'd be ideal. It'd be a ton of work to change this control.