Using dates as visibility rules

Hi,

I haven't seen this answered anywhere, so I'm starting a new thread.

I want a couple of checkboxes to show in a form only for leads created after a specific date.

I cannot find either "created" date or "SFDC created date" in the visibility dropdown menu for this.

It seems visibility works only with fields that are already on the form, so I tried to add "created" date or "SFDC created date" and hide it, to be able to use it as criteria.

I can't seem to add those fields to the form (perhaps because they are system fields?)

Is there a solution or workaround for this?

Thanks in advance,

Victor