As to SP6...
First extract SP6a into a folder. Then move into OEM folder on the CD you create. Say $OEM$CSP6a will copy the whole folder over to C:SP6a at the end of install.
Then make a sp6.cmd file:
c:
cd
cd sp6a
update -u -z
Create a cmdlines.txt file with the following contents:
[Commands]
\".sp6.cmd\"
I use \'.\' instead of \'C:\' because it\'s a reference and works better because it\'s relative.
Create an unattended installation script that contains the OemPreinstall = yes command. Place the cmdlines.txt file in $OEM$.
Remember, $OEM$ is inside the I386 folder. Place the cmd file in $OEM$C folder.
Hope this helps,