You should never create a form like this with the password hidden in it .. Simply create a login page which authenticates against the destination server and then set a cookie or session variable - or simply trust the information to begin with and send it to the destination site.
It looks like your trying to capture some user info before you send off the request for someone to pay for something correct? If this is the case - most online payment sites (paypal etc.) can send a confirmation email or http post which allows you to capture transaction information.
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