Just so you know you cannot at present ban someone using their nick in the ban mask without either adding a "ban nick" block or using services to add an SQline.
As for banning otherwise, you can use the /kline or /gline command.
/kline for a local server only ban and /gline for a global network wide ban.
Help on both can be found using /helpop ?kline and /helpop ?gline and at
http://www.vulnscan.org/UnrealIRCd/unre ... ercommands