It is supported on E-Flexwan + PA.
http://www.cisco.com/en/US/products/hw/modules/ps4835/products_data_sheet09186a00801df1d9.html
Check the protocols section in the above link "TCP, IPv4, IPv6, Multiprotocol Label Switching (MPLS), Ethernet over MPLS (EoMPLS), Frame Relay over MPLS (FRoMPLS), ATM over MPLS (ATMoMPLS)"
The customer facing linecard has to be the e-flexwan.
Regards,
Niranjan
(pls rate if post helps)