Beachhead studios announced yesterday that there where addressing the issue of not being able to send custom classes to game from elite.

"May 1, 2012 3:03 PM
KNOWN ISSUES WE'RE ADDRESSING: CUSTOM CLASS PUSH & CLAN OPERATIONS ENLISTMENT ISSUES
Pushing Custom Class to MW3 from ELITE Mobile App or Web

Currently, there's an issue with the ELITE Mobile App and Website that prevents users with either a Founders Winter Weapon Camo or Prestige Token Unlocked Weapon in any of their Custom Classes from pushing to MW3. This will be addressed in an upcoming web and mobile update.

Enlistments not registering

We're aware of a subset of Clans that are having their enlistment status change from "Enlisted" to "Not Enlisted" between the Start Time and End Time of a Clan Operation. We're investigating to find out the cause of this issue and get a fix implemented in an upcoming update.

Addressed in Most Recent Build

Clan Operation Leaderboard Discrepancies

We've implemented a new leaderboard tracking methodology the latest web build to prevent leaderboard discrepancies that some users have been seeing between MW3 and ELITE. This discrepancy was due to an issue caused by the volume of Clan data we were dynamically sorting to provide you with frequent updates about Your Clan's Performance within the Clan Operation details page. May 1st's web build has been architected with an emphasis on accuracy versus shortened update windows about Your Clan's Performance.

Clan Invites

We've optimized our invite system for Clans in May 1st's web build to correct an issue where users would sometimes receive a bad invite that couldn't be accepted. If you are stilll unable to accpet a clan invite, please ask the Clan Leader to send you a new one."