Using different versions of the Oracle Service Bus (OSB) runtime and the Oracle Enterprise Pack for Eclipse (OEPE) might result in annoying error saying that the version of the import artifact is not compatible to servers version. This could (but probably should not) quick fixed by changing the ExportInfo file inside the created jar archive. Look for the following line and change the value to your desired version:
<imp:properties xmlns:imp="http://www.bea.com/wli/config/importexport"> : <imp:property name="productversion" value="188.8.131.52"/> : </imp:properties>
Afterwards it should be possible to import the artifact successfully.