Hey. I've installed and configured JMS. Works well when slaves working in the same mysql master. But I can not master tables that are stored in other different database.
Just save the first 15 tables ad_agency component but there is left and continue past the tables.

The error I get: Fatal error:
Allowed memory size of 67108864 bytes exhausted (tried to allocate 64 bytes) in / home / midiario / public_html / (dominio.com) / libraries / joomla / database / database / mysql.php on line 462

As the message tells you, it seems that you don't have enought memory to replicate the website.
When you have have website with different DB and different MySQL user for each DB and that you don't have a shared MySQL user that is able to access both DB then JMS perform sequential read from 1 DB and write into the DB. So you need memory to read/write the DB content.
Otherwise, the replication is done by MySQL.

So check the PHP memory size.
If you have a small value like 32M or 64M, perhaps you need to increase it.