SAP Enterprise Portal (SAP EP) 6.0 with SAP ERP 2005 (ECC6.0)

Hi everybody we have a question about SAP Enterprise Portal (SAP EP) 6.0 with SAP ERP 2005 (ECC6.0).

Actually we are planning to migrate from SAP 4.7 and EP 6.0 [with Business Packages ESS 46C_50_4 and MSS 60_1_5 include the SP and TFIX] to SAP ERP 2005 (ECC6.0), but the big question is that possible?

Could we run SAP Enterprise Portal SP2 with SAP ERP 2006 (ECC6)? or

Is it necessary do an upgrade from SAP Enterprise Portal 6 to SAP Enterprise Portal 7?

Thank You in advanced!

Jose Luis