stephen,
do not try that if u want ur server to be running properly.remember the procedure of sbs 4.5 installation---WINNT.SIF script file is used to automate the installation.this file autodetects ur nic,modem,installs DHCP,WINS,PROXY,EXCHANGE,OPTION PACK automatically.SBS service packs r different from normal NT4 service packs.latest i think is 4.similarly tserver service packs r different.latest is 6.only in case of nt4 & backoffice 4.5 the service packs r same.SBS is called BACK OFFICE SBS 4.5. if u r in U.S.A then yours is 128 bit high encryption only.