Hi everyone

I have an issue I might need some input on. I'm working on a site where one of the features is a registration process with included online payment for membership. Basically, it's a few steps choosing type of membership, entering name, addr. etc in step 2, choosing payment method (online or invoice) as step 3 and finalizing the order accordingly. Due to rather complex app all this is based on, all steps have the same URI and standard web form posting is used.

My problem seems to be in the fact that lots of browsers use local caching of the internet pages, which prevents my app from finishing the job.

When online payment is chosen, user is redirected to an external site providig credit card verification. If verified, the amount is "locked" on the credit card and the user is then redirected back to my app for finalizing the order, meaning creating membership and withdrawing funds from credit card. This is where things go sour. I get repeated feedback that users fall back to step 1 of the process and also find the amount locked on their credit card, whereas I cant see anything being completed.

I have also tried having the credit card verification site redirect to an URI with an extra parameter at the end, so to "fool" the caching mechanism into not kicking in, but it doesn't seem to help.

My question is basically how is the caching issue addressed in these matters? It should also be pointed out that, while credit card verification site runs on secure site (https) my app does not (http).

Thanks for all help