Hi Brenden,
there seems to be an issue with the object definition for the database event key:
It's UomEntry and not as proposedAbsId.
You need to manually maintain the retrieval parameter in the INBOUND definition UI:
Or directly in the vBIU of your scenario (com.sap.b1i.vplatform.scenarios.design/vBIU.<yourScenarioName>/vBIU.xml):
...
<Inbound>
<Formatting>
<ruledoc/>
</Formatting>
<DataRetrieval delret="false">
<method>Retrieval</method>
<adapter>DI API</adapter>
<type>Service</type>
<mode/>
<ruledoc/>
<DIAPI_Service>
<id>UnitOfMeasurementsService</id>
<type>get</type>
<method>get</method>
<tag>UnitOfMeasurementParams</tag>
<keys>AbsEntry(UomEntryAbsId)</keys>
</DIAPI_Service>
</DataRetrieval>
<Channel Id="INB_B1_EVNT_ASYN_EVT">
<type>SAP Business One</type>
<mode>Asynchronous</mode>
<trigger>B1Event</trigger>
<obj>10000199</obj>
<ident>B1 Event</ident>
<idpar/>
<idns/>
</Channel>
</Inbound>
...
After that manual change activate your scenario and the retrieval of your UOM should be able via DI API.
Of course you can always use the alternative option to retrieve the B1 Event for UOM via JDBC, too.
Best regards
Bastian