SharePoint upgrade (2007->2010) missing feature

Hi.

I'm trying to mount content database from MOSS 2007 to SP 2010.

I get an error during upgrade:

"100.00%
Mount-SPContentDatabase : Upgrade completed with errors.  Review the upgrade lo
g file located in C:\Program Files\Common Files\Microsoft Shared\Web Server Ext
ensions\14\LOGS\Upgrade-20120325-183611-403.log.  The number of errors and warn
ings is listed at the end of the upgrade log file."

There (in the log file) I see the following information:

"Found a missing feature Id = [ea6d4080-ea47-40d5-9f83-3a48f77b556d]

The feature with Id ea6d4080-ea47-40d5-9f83-3a48f77b556d is referenced in the database [intrasync_wss_content], but is not installed on the current farm. The missing feature may cause upgrade to fail. Please install any solution which contains the feature and restart upgrade if necessary."

After I saw this problem (there was one more missing feature) I went back to 2007 (all this time it is "read-only") and deactivated, retracted and deleted those features/solutions, and repeated upgrade process with new backup. But one o them still creates trouble.

So, here is the question - what can I do more to fix it or can I start using this content database in 2010 "as is" and play with this feature later? Or second way will create more troubles? Test-SPContentDatabase says this error is "upgrade blocking".