Creditcard::validate_credit_card_number" doesn't validate card numbers

[mfarooqi]

A function in authorize.net "Creditcard::validate_credit_card_number" doesn't validate card numbers. It only validates CVV,

how can i validate CC number through this function prior to calling authorize.net... I was also about to... not to use authorize.net at all but validate CVV through this function "Creditcard::validate_credit_card_number()".. and use CC as offline CC.

On the other side of this class ... Creditcard, is not taking all the attributes "seriously". This creditcard class is located at /administrator/components/com_virtuemart/helpers/creditcard.php neighter that is testing CC number, not CCnumbers' relation with CCtype.

Can somebody please suggest me to validate CC under authorize.net prior to contact authorize.net.