how would secondary stitching would work in CJA

AJO is not using native email channel to send emails. Instead it sends custom payload to salesforce and salesforce sends email.
Now salesforce has email send/open/click etc data. Salesforce sends the data back to AEP(non profile enabled), which is then connected to CJA.
Both AJO dataset and salesforce dataset has personID as identifier.
AJO dataset has campaing name, and campaingn TaskCode which is unique for each email touch point. Salesforce also has the TaskCode but not the AJO campaing name.

Now if I breakdown the JourneyName by Email metrics (open/click) etc, it shows 'NoValue' in the report.
I have tried binding of JourneyName dimension with the Dimension related to email open/click, that still shows 'NoValue'.
I have tried binding of JourneyName dimension with the TaskCode dimension, that still shows 'NoValue'.

What am I missing here ? Do we need some sort of secondary level of stitching to link TaskCode from Journey dataset to salesforce dataset ?