CRM Opportunity - Web Dynpro ABAP

Hi,

We have a requirement to create a UI for a business requirement which is like CRM Opportunity in SAP CRM. Our customer don't like the SAP CRM Web UI Screens. They have a legacy system and they want to create a custom UI for them.

I am thinking to create it in Web Dynpro ABAP. Did anybody work in Web Dynpro ABAP in CRM....Any limitations????

Please suggest.

Thanks,