I have a windows 2003 server running Plesk 8.1

I just purchased AWBS billing system and they tell me I have to have php configured with openssl.

This is a quote from their support dept.

"Unfortunately PHP is usually compiled with a default set of features. It looks like yours is missing OpenSSL. You will need to get your server admin to add OpenSSL support to your PHP, or will need to do it yourself."

Does anyone have any idea on how to do this?
Any help appreciated.