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 firstname.lastname@example.org. (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.
If you want to be able to send an affiliate URL from your AWeber list, you can use the "Affiliate ID" field for this.
The format of a Nanacast affiliate link is like this: http://nanacast.com/vp/OFFER_ID/AFFILIATE_ID
So assuming you've created your the "Affiliate ID" field as a custom field in AWeber and are capturing it via your parser, it is then available to use in your AWeber email.
Example: If your offer ID were 123456, and you named your custom field for the affiliate ID, "custom_affil_id" then in your AWeber email, you'd build your affiliate ID like this:
Keywords: Custom fields, affiliate ID, Aweber