Hello tevilu:

You ask about a possible translation to Spanish of the English “post-it” as a term.

ANALYSIS

In your case, I think that we have to treat “post-it” as a unique word like in English and not as two (2) terms. This implies that “post-it” is not the same that “post it”.

I searched in Wikipedia in English and Spanish and I found that in Spanish the term “post-it” has the following explanation: “Los post-it o pósit son unas pequeñas hojas de papel autoadhesivo de varias dimensiones, formas y colores, aunque predominan en paquetes de varias hojas pegadas entre sí.”
URL: http://www.proz.com/kudoz/english_to_spanish/computers:_syst...

I checked in other bilingual technical glossaries and I didn’t find other references about the complete noun “post-it”.

MY SUGGESTION:

My suggestion: use in Spanish “post-it” or “pósit” similar to Wikipedia.

I hope this proposal helps you in your work.

Regards

Domingo