I understand ... but I believe it can be done

If you want people to get a form in the UI you can append &cf=(internal id of form) to the url. If you want a specific form to be applied (say you want a certain email or printed template to be applied) you can set the field "customform" with the script. We do this sending BOL's where we change the form via script, send the BOL and then change the form back via script.

Have you ever seen this done in the past? I tried loading custentryform, entryform, form or customform, none work

Oh I misread the question. I don't think the custom form record is loadable. I thought they were attempting to change the customform use on a record with script.

here's what I'm really after: you know how the form has checkbox for which fields should appear on the form, and which shouldn't. i need access to that information about the form.