The partner links are placed in the left and right margins of the process diagram. Service requestors are placed on the left side, service providers are placed on the right side. To define the role and to choose the appropriate side for each partner link the IDE uses the order of roles defined for the partnerLinkType in the WSDL file. The role defined first in the partnerLinkType in the WSDL file is considered to be a service role, the second defined role is considered to be the role for the requestor and callback receiver. If the roles are defined in the reverse order in the WSDL file (the callback receiver role is defined in the first place, and the service role in the second place) then you get the improper partner link layout in the BPEL process diagram, though the operation is not damaged. If a partner link appears on the wrong side you should go to the WSDL file and swap places for the role definitions in the partnerLinkType.