Seems driver is installed in core "usblp".
Maybe wap-0007 ROM has an init or hotplug changes for the printer system. I can't test it. Sorry.
If you can get wap-0007 sources, check the MGB100/rootfs/bak.etc/rc.d/* and compare it with the ROM
check hotplug(binary) hotplug.sh, inittab, rc.* if they are diferent from the ROM, copy or change it.
rc.bridge is the only file changed in the source to get telnet server.
If you find the changed files, post here and we will have printer support too
