Unfortunately right now there is no native feature in the Unbounce page builder that will allow you to customize the case of form field IDs. You might be able to do this with some custom script like the example below in your page’s ‘Head’ section, to intercept the form submission for this:
But again since this isn’t native to the forms, we wouldn’t be able to say about any problems that might come up with the form and form data. I would recommend testing this out to see if it works for what you need.
Alternatively, we have a webhook functionality that, with a little bit of development from your end, you can use to POST to your CRM. This feature includes field mapping which should help with by-passing a case sensitive field attribute. You can learn more about webhooks here: http://support.unbounce.com/entries/3…
Hope this helps a bit Michael!