Hi Steffen,
Basically this particular info parameter is getting updated through BAPI_EH_POST at a later time as per design.
So Would not it be fine to reset the value through EH Update function...instead of using EM -AI way.
Because in case of EM-AI way, We have to populate the old data in the enhancement, then in the custom info parameter extraction function module..we have to write the logic to push action as delete for old entries which are not mentioned in the new data (parameter name+index wise)..
Regards,
Ratnakar