Expression Engine Rebuild Database for members??

I am trying out the trial of amember to see if it will work for our project using EE.

When I signup everything is fine, but the member is not added to the EE members database unless I manually click REBUILD DB in aMember admin control panel.

My aMember and EE are using different databases but they are set up in the setup/config plugin area.

I have my DB user/pass etc all selected, I have my EE group selected as members. But the only way to get new members into my EE database is to manually rebuild the DB.

There must be an automated way but how do I know it will work before I purchase?

in my EE plug setup/config
I have:
Expression Engine Db and Prefix set to user_blog.exp_
where user_blog is my EE database name and exp_ is the prefix

MySQL Database User: user_blog

MySQL Database Hostname: localhost

Expression Engine Group: Members

I have given both the aMember and EE mysql users access to both databases.

just to be clear, the aMembers that sign up are added to the EE database ONLY WHEN YOU MANUALLY CLICK REBUILD DB,

So it seems the connection between the 2 is fine, why do the new members who sign up not get automatically added to the EE members db? Seems useless if this is not automatic.