[ic] Authorize.net - invoice number

[M Dell, In the Sun, LLC]

I am looking to pass the invoice number from Interchange to the
Authorize.net email sent to the merchant.  I see the IC variable is:
mv_order_number and the Authorize.net variable is: x_invoice_num, but I
don't see where to put this in IC.

Thanks
M Dell - In The Sun, LLC