I have had much grief getting Linuxconf to work with assigning virtual IP addresses. After my own hacking, I discovered two major flaws: 1) Ranges of IP addresses are not supported. Only one at a time. 2) Furthermore, the files it creates "ifcfg-eth0:0", "ifcfg-eth0:1", etc., all also require a line reading 'DEVICE="eth0:0"' as well. If this line doesn't exist, the files are ignored and thus the IP aliases are ignored.
I believe that this is all fixed by the current initscript errata release. Please reopen this bug report if you upgrade and find that not to be true.