Questions Adding navigation to CRActivity.Source field in GI

I'm trying to create a GI using the CRActivity table for some dashboards. I would like the CRActivity.Source field to click through to the respective source entity for the Task. I've set up the Navigation Parameters thusly:

However, when clicking the link in the Source field I'm seeing the following error message: Cannot open this record for editing: The form SO301000 does not contain it.

Any suggestions how to go about correcting this? I suspect it has to do with this field containing both the OrderType and OrderNbr combined, but I'm not sure how to work around that.