Hi Bob,
If you can see (ping 

 ) the interface from the inside, but not from the
outside, it could be a routing-problem, or maybe you assigned the aliases to the internal interface (standard = eth0) instead of to the external interface.
You can check the mode using the command 
   /sbin/e-smith/config show EthernetAssign 
It reports normal (eth1=external) or swapped (eth0=external)
For the *external* interface, in normal (not swapped) mode, use ifconfig eth1:1 
 for the first alias-interface, ifconfig eth1:2  for the second alias, etc.
When using scripts, copy the /etc/sysconfig/network-scripts/ifcfg-eth1 to /etc/sysconfig/network-scripts/ifcfg-eth1:1
(should ifcfg-eth1a work too? dunno )
Change the contents of ifcfg-eth1:1 to suit your needs. 
After that, a 'service network restart' should do the job, really.
BTW, If you want to assign more aliases (e.g. a range of IP-numbers) at once
to one interface, take a look at the contents of the script 
/etc/sysconfig/network-scripts/ifup-aliases. It's all explained in there.