Sendmail disregarding mailertable

I have an out-of-box package-based installation of Sendmail on a CentOS 5.4 machine and am attempting to configure it to act as the public-facing relay server for various internal servers that handle e-mail for various domains. All the proper MX entries point to this public-facing server.

I've performed these steps so far:

• Installed sendmail via yum, which gave me stock sendmail.{mc,cf} files.
• Ensured that the mailertable option in sendmail.mc is defined and not commented out.
• Ensured that the Kmailertable option appears in sendmail.cf after running make.
• Edited mailertable to include the domains I wish to relay to internal servers in lieu of using MX. (i.e., domainx.com: relay:mail1.internal.com)
• Run make and ensured that changes were committed to mailertable.db.
• Restarted sendmail.

The problem occurs when I actually attempt to relay mail destined for one of the mailertable domains through this box. The resulting entry in maillog reports config error: mail loops back to me (MX problem?) and subsequently DSN: Local configuration error. At no point does it mention attempting to use the relays I've explicitly provided; it is doing pure MX-based routing instead. This is the same end result I get when I disable mailertable, so it appears it's completely disregarding it altogether. As a side note I've attempted using domainx.com: smtp:mail1.internal.com with no change.

Is there a step in the process that I'm missing to get this working correctly?

OK, I steered you incorrectly in your last question. The proper format for mailertable is:

domain.com         relay:some.other.system

...ie, no colon after the intended destination.

Sorry about that -- going too fast on my part. I've fixed the other question too so it won't mislead people in future.