Updating Attributes at Position Level in SRM

Hello,

I need to update the extended attributes 'Approval Limit' & 'Output Limit' at the position level in SRM Org structure. Could you please help identifying the right FM to use.

I have tried the FM BBP_UPDATE_ATTRIBUTES but it seems it works only for Users and Org units. I am not able to update the position.

Need help.

Thanks,

NB