If you need to change name of database in config, it is recommended , when generating Business Entities, in Advanced tab to set tick to Metadata Class Should Ignore Catalog.
To implement join for multiple tables it is suggested to create a view that brings joined tables. They will support joins in a future version.
There are useful EntitySpaces Query API and Query API Samples.
Filling an EsCollection out of an ordinary DataTable not supported,but you can try
public bool CustomPopulate(DataTable dt )
this.Table = dt;
To Clone EntitySpaces entities - the thread suggests binary serialisation(seems not always working?) and column by column copy.
The ASP.NET demo source can be downloaded using Trial version and solution GridLoader.sln located under GridLoadersASP.NETC#GridLoader folder
See also EntitySpaces DotNetNuke ASCX Admin Grid Template Suite Released
EntitySpaces and LINQ and LINQ to SQL-Aug 2007 thread .