try something like this:
xconfmanager -s "publish.cadconvert.PROE=com.ptc.wvs.server.publish.CadConvertPROE,useworkerdownload\=$(wt.home)$(wvs.dir.sep)auth.properties,referencedfiles\=true" -t codebase/web-inf/conf/wvs.properties -p
Pay attention where the wvs.properties is located. The above is for 10.2. In 10 and 10.1 it's in the codebase folder.