One of our customers came up with his own question and answer solution regarding exposing information from InfoPath forms and I think it will be useful for a lot of people, so here it is:
Q: Is it possible to put information from an Infopath forms server web form into the approval notification from Nintex? For example, say my Infopath web form has a vacation request date included and I want to put that into the email notification that Nintex sends. This would help the approver determine if he/she should approve the workflow.
I tried exposing the columns in Infopath when publishing the form, but that doesn’t seem to have the desired effect.
A: I found the solution to the problem on the Microsoft forums. When updating an existing forms server form to add columns exposed from the form to SharePoint, you need to restart the feature at the site collection level. Do this at Site Actions-Site Settings-Modify All Site Settings, under Site Collection Administration-Site collection features. Find your form and Deactivate it then Activate it.
As soon as I did that, voila! The columns appeared for Nintex to use.