InfoPath Dev

I want to create a form that uses an external sharepoint list for validation.

The information in the sharepoint list is confidential and I don't want it stored in the InfoPath form.  (Sharepoint list houses 2 columns, Evaluation code (number) and Maximum pay increase (Percentage)

IE-  A person receiving an evaluation code of 1 is eligible for a 0% pay increase.

How do I validate against information in the sharepoint list without storing it in the INFOPATH form?   For example... User of the form enters a pay increase request amount. (Of X percent.)  After entering request amount, I want infopath to compare evaluation code (In form), match it to the evaluation code in the Sharepoint list to determine if the pay increase amount is valid.

My problem is I can't seem to filter the validation based on evaluation code. (A person with a Eval code of 1 is still showing as eligible for a raise...)

Any ideas?

**EDIT** - I believe i need to create a rule based on an expression.  The only problem is I don't know how to use Xpath. 

So, what would you like the form to do if it isn't valid? Or if it is?

You don't want to store the evaluation code in the form, but you say "I want infopath to compare evaluation code (In form), match it to the evaluation code in the Sharepoint list to determine if the pay increase amount is valid", which confuses me a little bit.

In general, you should be able to use a rule to compare the evaluation code in the form (if it is in the form) to the data returned from your Sharepoint list and get back the pay increase amount from that data source. I'm including a simple sample that uses an xml file for a secondary data connection so you can look at it. You'll see there is a filter on the field that I am using in the rule on the eval code field. That is what you'll want to look at more closely to implement in your form.

Right click the link in the header, and select save as. Save the sample locally, and then right click the saved copy and select Design. Preview it and select an eval code from the dll -- the percent will populate in the text box below.