Somewhere in a previous version of fwbuilder I was able to create network objects like:
10.0.128.0 / 255.0.255.0
But now (version 184.108.40.20699 Mac OS-X) I get the message:
"Netmasks with zeroes in the middle are not supported"
For a Cisco IOS ACL it generated valid wildcard masks in the past.
"10.0.128.0 255.0.128.0" became cisco wildcard "10.0.128.0 0.255.0.255"
I have multiple locations with networks for example: 10.64.x.x/16, 10.32.x.x/16 etc... and in each location 10.x.128.x trough 10.x.255.x are client vlans.
Maybe you could create an preference option like: "I want to use zeroes in netmasks, Yes I (pretent to) know what I'm doing and know that these objects are not compatible with all types of firewalls"