Multiple domain services in one project

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C#

Silverlight

Hello,
I have a project, Silverlight Business Application. I created .edmx file, and based on that, domain service. Database has many entities, so I decided to divide entities in few edmx files, so I could create few domain services.
Everything was ok with the first one. Then I tried to add another edmx file, and changed Custom Tool Namespace. Now first edmx has Custom Tool Namespace set to Project.Web, and the second one Project.Models.Partner.
But, when I compile project, I get errors. Somehow, classes from the first domain don't recognize namespace. And if I had

public partial class Domain
{
     public virtual ICollection<domainvalue> DomainValues
     {
        get;
        set;
     }
}

 public partial class Domain
    {
        #region Fields and Properties
        public DomainValue CurrentDomainValue
        {
            get
            {
                return this.DomainValues.FirstOrDefault();
            }
        }
        #endregion
    }
</domainvalue>

after adding the second edmx, I get an error at this line:
return this.DomainValues.FirstOrDefault();
it says it doesn't recognize the DomainValues...

Could someone please explain me what is the procedure of creating new edmx file, and domain service, if I already had one?

Best,
Lucky