Need a TOTAL field without the currency symbol in Invoice email notification

Need a TOTAL field without the currency symbol in Invoice email notification

I have customised the invoice email notification template to include a URL that will then populate a payment gateway with all relevant payment fields.

eg.

(above link is how ZOHO generates the URL..Note the %Total% (last parameter of $112.22) includes the currency symbol
The problem is that the TOTAL field always includes the currency symbol (eg. $20.00).

I just need the number, stripped of the currency symbol, otherwise the payment gateway requires the field to be manually edited before submission by the customer, or each invoice email notification to be manually changed to remove the currency symbol.

SUGGESTION: have a %TOTAL_num_only% field that strips the currency symbol from the invoice total.