Credit card Surcharge

Hi, 

I have enabled the Online Invoice Payments in AR Preferences, added a credit card surcharging to "pass the credit card surcharge on to my customers" and nominated an account.

I have resent the invoice on email via MYOB Sales to the customer, and now just received an email that the amount excluding the surcharge has been paid.  Is this normal?  How can I check that the surcharge has been paid?  I'm doing larger sums, so the 1.8% adds up for us.

I just then went into an existing link for a client and tried paying with my own credit card and the 1.8% wasn't being added to my charge.  

Can you please confirm: All invoices paid via the online links will add the surcharge, or only those issued after today (the day I enabled surcharge to be passed on)?