Order ID unspecified for adobe commerce implementation

[banerjee_pritha_omds]

Hello all,
We have a adobe commerce website implemented with adobe experience platform connector extension and adobe launch. We are also using adobe client data layer and AEP Web SDK schema for data collection. 
I have created a processing rule to track the Order ID from the data layer.

I have used purchaseordernumber as well instead of purchaseId but nothing is showing the proper value in the report suite. It is showing Unspecified for every order.

If anyone can help me figure out what point I am missing that would be very helpful. Thanks in advance.

[Jennifer_Dungan]

Is your eVar set up as a Merchandising eVar?

If set up in Product Syntax, it cannot be set in Processing Rules since the eVar must be passed as part of the s.products string (and s.products isn't available in processing rules).

If set up with Conversion Variable Syntax (I haven't used this setup) I know that to set the instance, both the product and binding events must be set in order for the instance to be set, but I don't know if that would also affect the value....

I don't use the Web SDK yet, so there may be other factors at play, but the since this is an order, I suspect that this would be set up as some type of Merchandising eVar which comes with challenges.