Hi guys,

I'm really complicated trying to integrate PayPal with OsCommerce. I have set up PayPal Express Checkout, for what I used this info:

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View or Remove API Signature

For preconfigured shopping carts: Copy and paste the API username, password and signature into your shopping cart configuration or administration screen.

For building custom shopping carts: Store the following credential information in a secure location with limited access.
Credential API Signature
API Username info_api1.mecanica.com.au
API Password ********
Signature ********
Request Date 11 Feb 2010 11:35:11 AEDT

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At the moment I'm running an original OsCommerce (I just want this to work). I'm working with Sandbox. The message I get all the time is: "Security header is not valid"

Is there something else to set up? What might be wrong with the configuration?

Then, when I use PayPal Website Payments Standard, everything seems to be alright, I go to PayPal web page, I pay, I get the "success msg", and when I go back to my web site, I'm redirected to "checkout_payment.php" and it's like the operation NEVER happened.

Please! I need help, at least one of them working!

Many thanks,
Sebastian

p.s. Just in case it changes sthing, I'm in Australia, selling in AUD! Cheers.