How Can I Create an Oauth Signature and SAML Assertion For Intuit Partner Platform?

I am trying to connect to the Intuit Partner Platform to use the new AggCat API but I am struggling to get the Oauth Signature and SAML assertion setup to authenticate and use the API. I have looked at the PHP DevKit for QuickBooks as an example but I think that is a different authentication process anyway. Are there any examples of how to use PHP to authenticate and use the Intuit AggCat API?

Solution

There is a PHP sample available on github, but I still have not been able to figure out how to get the SimpleSAMLPHP setup working. Here is a link to the sample on github: phpaggcat.

If anyone has more luck with the github sample using SimpleSAMLPHP and can generate a more complete answer, I would appreciate any tips on making it work.

Edit 08/04/2013

I looked at this again recently and got it working. See my answer here.