Please don't test your biller setup with GXBill's test account—it won't work correctly.
Setting up on GXBill's Website
Register a GXBill account. Record your GXBill
Merchant ID and password. Setup your sites; for each site, record its
GXBill Site Code.
Set the password script to:
Replace linkdomain with your Link Domain.
Set up GXBill in NATS
Go to the Billers Admin, select GXBill from the drop-down, and click Add.
In the ID field, enter your GXBill Merchant ID and password.
Go to the Sites admin, edit or create a site, and go do the Biller
Details section. In the Site Code field, enter a GXBill site code.
Versions 3.1.67.1 and later
GXB now has the ability to return to Nats after a successful signup. To use this feature check Allow Return? in the Site setup. When checked, GXB will return the surfer through Nats (allowing Nats to show the approval and denial urls/templates).
Go to the Special Payment Options section, select GXBill from the Biller
drop-down, and fill in the join form text; for example: "No Credit Card?
Pay by Phone." If GXB gives you a Type to fill in you can fill in the 'Type' field in the Biller Codes column.
Geo-Target Banners
GXBill can replace the Pay by Phone text with the words "Pay by Phone"
in a user's native language. To enable this feature, edit the NATS
join template and make the following change:
Remove the following line:
<input class="join_button" type="submit" name="special[]" value="">
Replace it with the following line:
{if $special_options[option][1] == 'GXB:361'}<input class="join_button" type="image" src=http://www.gxplugin.com/banners/image.php?id=MERCHANTID&site=SITEID&skin=default
name="special[{$special_options[option][1]}]">{else}<input class="join_button" type="submit" name="special[{$special_options[option][1]}]" value="{$special_options[option][0]}">{/if}
Complete you change by logging in to your GXBill account and getting the
extra banners. In the new code above, replace MERCHANTID and SITEID