To get your client's affiliate id into AWeber, first add "Affiliate ID" as a custom field in AWeber for your list. It should be spelled just like that, with capitalization and space.
Then create a custom email parser in aweber, not the default nanacast.com parser. You may need to contact AWeber for help with this.
The "From email" for the "Trigger Rule" should be email@example.com. (Tip: Use the preset email parser for nanacast that is already in your aweber account as a reference when creating your custom parser)
Then add a new rule for each custom field you want aweber to record.
So for Affiliate ID you would add a rule to your parser called "Affiliate ID"
Note: The fields "name", "email", and "Affiliate ID" are already included in the email we send to the AWeber parser, so you don't need to do any additional configuration within Nanacast.
Keywords: Custom fields, affiliate ID, Aweber