Please don't test your biller setup with Linkpoint's test account—it won't work correctly.
Setting Up on Linkpoint's Website
While registering with Linkpoint, make sure to take down the PEM File Location and Store Name/Number that were provided to you by Linkpoint. This information will be necessary for setting up Linkpoint API as a biller in NATS3.
Setting Up Linkpoint in NATS
When prompted, fill out your transaction and chargeback fees, along with when you wish to deduct them. Fill in your PEM File Location -- this is the location of the digital certificate that Linkpoint issued to you in their Welcome E-mail. Enter your Store Name/Number next -- this is your Linkpoint username and password.