Assuming that your HEURSUPP is a work entry type that you've added, you can create a new payroll rule for this work entry type to show up on pay slips. You'll most likely want to set it up with a Python Expression condition like this:
result = 'HEURSUPP' in worked_days and worked_days['HEURSUPP'] > 0
You can use something like the following for the Python condition:
OVERTIME_MULTIPLIER = 1.5 # Or whatever you need
result = worked_days['HEURSUPP'] * OVERTIME_MULTIPLIER * contract.hourly_wage
You'll of course need to configure the other fields to meet your needs. Specifically, take care when choosing the category so that the result is added appropriately to the gross pay if that's where you want it.