There are a number of ways to resolve this issue. First, a wrapper WSDL can be created, either manually or using a BPEL authoring tool, to import the original WSDL file and add the partnerLinkType section to it. The advantage of this option is that changes in the original WSDL are automatically reflected without the risk of the wrapper WSDL getting out of sync with the service.
Second, many service publishing frameworks, such as Apache Axis, allow the WSDL to be edited and re-saved. The partnerLinkType section can be added directly to the original WSDL in that case. Even if the publishing framework does not allow for such editing, it is always possible to save the original WSDL in another location (URL), make edits to it, and re-publish it at the new location, to make the Web service "BPEL-friendly".