How to add Element Entry in Individual Compensation Plan

Hi Team,

I created "MBO Target (%)" as Element

I aim to add it in the Individual Compensation Plan I previously created

However I'm being not able to achieve it:

because I'm not finding the element in "Payroll Element" list:

Could you please give me any suggetion/support?
Thanks in advance!
The goal is :
1. to "recall" this information in "Other Compensation" during the Job Offer step in Recruiting module

2. Basing on this Element Entry to create an Eligibility Profile

Tommaso