MigrateKit is a module that complements Migrate module to allow import items into multi-value field collections.
The weak point of Migrate is that it uses map id's as base for count. So, if there is more than one same id in a database (that belong to the same item and will be imported as multi-value field collections), it can't handle them. This module presents changes subclasses form Migrate module and the Field Collection migrate inc file, that allows it to bypass this limitation.
Migration Kit creates a column of unique integers ("muid" column), that serves as a map for importing multi-value field collections.
To use MigrateKit, install it as a Drupal module, and use it's classes, MigrationKit and MigrateKitDestinationFieldCollection instead of the corresponding migration classes.
The sample migration inc file is located in the sample folder.
Please note, that watermark field and the map specs have been moved into the lower lever migration class, since they remain the same, based on a muid field.
Drupal code git: http://drupalcode.org/sandbox/alexrayu/1795572.git