CiviCRM Community Forums (archive)

Hi!
I have a query regarding a site I am currently working on. My client have a number of different types of memberships, but all of the same value. Some of the site was done without CiviCRM and generally, due to time and money constraints, a lot of that site is not being changed. However, I am trying to integrate a few CiviCRM functions into the site such as Events and Contributions. Which leads me to my query. The current side of the site for selling items works well but I was thinking of linking it through to CiviCRM from its current page, and so was thinking of a way of doing this. I've created one contribution page which should in theory be sufficient. The link to this page is index.php?option=com_civicrm&view=Contributions&Itemid=37. What I was then thinking of doing was editing the link so for each product it would be slightly different, i.e. index.php?option=com_civicrm&view=Contributions&Itemid=37&Prodid=1. Therefore each product's id would be carried over in the link. My question is how could I capture this ID. I was thinking I could use a field in the Contributions table that is not being used, such as Source, could be used, and that I could use a GET clause to take this ID into that field. Does anyone know how I could do this? Is it possible to edit the form that does Contributions so that I can try and do this? I'm still new to CiviCRM and this could be really helpful to me.
Thanks!