Shipping and Payment Module

[Nikx]

First, forgive my poor english.
How can I customize shipping module, and how shipping charge/rates can be automatic show in checkout page/payment, i'm usually ship using GED, TNT or PCP.
I've look in UPS shipping module and i customize that module for TNT but, the price/rates can't automatic show in checkout page/payment.
For payment module like moneyorder, where is constant 'MODULE_PAYMENT_MONEYORDER_PAYTO' defined, I've customize moneyorder payment module for banktransfer module where constant 'MODULE_PAYMENT_BANKTRANSFER_PAYTO' is refer to the bank account number not to store name or address, but it show store name and store address

Please help me, I'm new in Zen Cart

[kobra]

I've look in UPS shipping module and i customize that module for TNT but, the price/rates can't automatic show in checkout page/payment.

UPS module uses a link to the UPS calculator for rates...I am not familiar with TNT and do not know if they have a web accessible rate calculator or not.