Adding a binary null to a value using attr_rewrite

Hi. I'm using attr_rewrite to add a Class attribute in my auth- reply packets. I need to include a binary null-byte in the value, but I cannot figure out how to do so. If I add a verbatim null-byte in radiusd.conf, the string is truncated there in the reply packet (seems like the code interprets it at some point as the string terminator). If I write \0 instead, it is simply ignored. Does someone know how to accomplish this? Thanks -- Tore Anderson