Thanks. We'll stick to authorize.net for now.
Tested the session variables and it appeared to work. Eg, session changed from NULL to test and the session id did not change.
Where to from here?
To Test you servers session management:
1) Click here to Set Session variables
The link above uses a URL variable to trigger setting a session variable
2) Click here to test session variables
This link does not contain the URL variable, so it will not set the session variable again, but the session variables value should not be changed.
Session Test = test
(When the page is first loaded, the session variable test will = NULL, when you click the first link, the session variable test will be set to test. Clicking the second link will only reload the page, the session variable test should still equal test, if it equals NULL, your server has a problem with session management.
Session ID = 6cdb41e4a96d542a6c784015768655ba
(NOTE: if sessions are working correctly, the session ID should not change.)