Once upon a time a long while back, I encountered this problem on my current Linux LPAR. Apache would start, and then when IPL was done it was gone and I had to start it manually. There was something to do with giving a task that handles the initial startup of stuff more time to complete, as it gets killed at the end of the IPL and anything it directly spawned (such as an apache startup command) is killed also. Giving it more time was the key.
I just don't remember what 'it' was.
