Ok, i was able to figure out how to get the customer name transmitted to my list.
Hope this helps others with integrating Interspire Emailmarketer too.
Here is the part from the api for the name, and how i filled it:
<customfields>
<item>
<fieldid>14</fieldid>
<value>'.$firstname.' '.$lastname.'</value>
</item>
</customfields>
As fieldid, you simply set the id of the custom field you use for the customer name on your list in Emailmarketer.
Here's how to go about it:
Step 1: create a custom field in Emailmarketer (or decide which existing one to use) for representing the customer name on your list.
Step 2: create a sign-up form for your list and add the customfield from Step 1
Step 3: Get html for your list and identify the field id for your custom field. Look for CustomFields[xx] - where xx represents the number of your custom field
Step 4: insert your custom field id (number xx) into api code as shown above
Step 5: set estore variables as "<value>"; for instance
<value>'.$firstname.' '.$lastname.'</value>
if you want to use first - and lastname like me.
Perhaps '.$CustomerName.' will work too (haven't tested that)
One last hint:
I simply inserted the (complete) api code after line 277
$retrieved_product = WP_eStore_Db_Access::find(WP_ESTORE_DB_PRODUCTS_TABLE_NAME, $cond);
in the auto_responder_handler php
and left the rest of the code unchanged.
That worked like a charm ;)
But i don't know though if there might be a better place to insert the code.
Good luck with your Interspire integration ;)