oracle11g - BPEL 2.0 Dynamic Partnerlink error: fromValue is not a sref:service-ref element -

oracle11g - BPEL 2.0 Dynamic Partnerlink error: fromValue is not a sref:service-ref element -

i want invoke web service bpel 2.0 dynamically, seek update partnerlink endpointreferencetype, when compile there warning

warning(107): from-spec of "ns4:endpointreferencetype" not compatible to-spec of "ns1:process"

and when test request web service got error

<env:fault xmlns:ns0="http://docs.oasis-open.org/wsbpel/2.0/process/executable"> <faultcode>ns0:selectionfailure</faultcode> <faultstring>fromvalue not sref:service-ref element</faultstring> <faultactor/> <detail> <exception/> </detail> </env:fault>

the assign script is:

<copy> <from>$endpointreference</from> <to partnerlink="service1"/> </copy>

it's running on bpel 1 next script

<copy> <from variable="endpointreference"/> <to partnerlink="partnerlink1"/> </copy>

anyone has same issue? share solution please

cheers

oracle11g soa jdeveloper bpel