Right now, the setacls XML API call does not provide access to the reseller limits options, only to the reseller ACL list.
You could POST the variables to:
https://IP:2087/scripts2/editressv
if you wish to automate the process. Take a look at the source in the Edit Privileges/Nameservers for the specific variable names that are sent to editressv.
Let me know if you have any questions.