Google Tag Manager and <iframe> Help needed

I need some help from experts in Google Tag Manager.
Does anyone have an idea how to implement a trigger on <iframe> element that you can't get access to?
Concrete problem is: I need to put Button click trigger on the form, but the form is in <iframe> that I don't have access to so I can't do it the standard way.
Does anyone have some idea?

I don't understand your problem clearly, Please let us clear more details.

AnalyzerIT said:

I don't understand your problem clearly, Please let us clear more details.

Click to expand...

Ok, I need to implement conversion tracking trough GTM. Let's say I want to do it by button click. So when someone clicks "submit" button, I want that to be a trigger for my tag.
Problem is, the form is embedded in iframe on the page, not actual part of the page. So I can't do it the standard way.
I know it is possible if I could install GTM also on the page (form page) but I can't do that.
So I'm wondering is there some other way I could record that Button click trough Google Tag Manager.

Hope this makes it clearer...