Exchange Front end/back end configuration

Our exchange IS exceeds the 16 GB limitation that exists for Exchange Server 2003 Standard Edition.

However, now we are looking at installing a front end server to serve OWA and possibility some Blackberry or OMA services.

Can I install a Exchange 2003 Standard front end with a Enterprise backend?

I know I can use Standard as a front end server. I have not been able to find any references with using Standard with Enterprise versions.

Thank you