I attempted to prepare a slipstream SP3 CD by arranging all the installation components and issuing the "integrate" command from the command prompt.  I get an error stating, "This Service Pack cannot be integrated into a destination that also has integrated Software Updates"

After Googling, I understand this is likely due to some service pack updates existing on my Dell XP Reinstallation CD (SP1a).  I see some advice on other forums to delete the svcpack files and replace the svcpack.in_ file with one from another XP installation disk, replace the deploy.cab file with one related to SP3, etc.

Here is an example of such advice: http://vbdotnet.home.comcast.net/~vbdotnet/XP_SP2.htm

I feel uncertain these tweaks will result in a reliable XP installation CD.  Does anybody have experience with creating a functioning SP3 slipstream with a Dell reinstallation CD?  Is the method I describe reliable?  Does using something like nLite resolve such issues?

Thanks!