Just bought a fancy new IBM server to install into an existing tree.
This is the first server I've tried to install with only USB ports and no floppy drive.
It has just a CD/DVD and RAID 5 with 3x 500Gb HDs and a fourth hot spare, oh and 2x Broadcom NICs.

Wanted to stay with SP6 since this is the level of the other network servers and SP7 has been accused of causing other problems. (I later discovered to my cost that this accusation would appear to be deserved!)

Problem 1
The LAN, Storage & RAID drivers for this server do not exist in SP6 :( although they do in SP7 - This was a nice surprise :) or so I thought !

Problem 2
During SP6 overlay installation it seems impossible to add a driver from the SP7 CD. Attempting to add an unlisted driver by browsing to the SP7 CD reports that there are no LAN or storage drivers in the designated paths, although in reality there are plenty, in fact all those included in SP7 !

My solution 1
Break out of the installation and manually copy the correct drivers to C:\NWSERVER\DRIVERS then resume the installation.

Problem 3
Having broken out of the installation, I don't seem to be able to resume the installation without formatting the C: partition.
Rebooting with the installation CD offers two choices
a) Format C: and lose all existing files, including the drivers I just added
b) Exit

My solution 2
Install SP7 overlay and to hell with the consequences
First attempt failed with so many errors I couldn't believe it. Consideringthis was a new server and a fresh copy of the SP7OS & SP7PROD CDs I was surprised.
I had installed both server NICs on consecutive IPs which, from some of the error messages, might have caused a few of the problems.
Second attempt, installing only one of the NICs, seemed to go like a dream :)
Oh, but that was until I began to add pools and volumes. Each attempt was met with a pool creation or access error, even though the new creation was visible in the NSSMU screen. Then all hell let loose and the new server stopped communicating with the rest of the tree resulting in the usual lost connection NDS errors irritatingly bleeping away, even though a logged in workstation could still see directories on the new and other servers. Running up ConsoleOne revealed loads of ? against all the new server resources and in short the installation was a disaster, since there seemed to be too many errors to fix.
Oh and I also got the DSAPI.NLM error saying (LOADING in red text) that poor old Alan Thompson got too. I can now very much sympathize with his predicament and, trust me Alan, your problems were SP7 generated !
At least I'd only travelled 100 miles to site each day rather than to another continent !

Several more abortive installations were attempted yesterday and today using SP4A and later base installations from hand carved CDs, with added in drivers, without success. (I avoided using SP5 since Virtual Office options are suppressed in this overlay and we use this facility)

I appreciate that the answer to this question is probably pretty basic, but it eludes me at present. Maybe I'm just losing it after 2 days of depression !
How can I add my SP7 LAN, RAID & Storage drivers into an SP6 overlay installation and continue with the installation ?