Reposting this snippet for people who want to make an association on one side of the chain:

I made this code a year ago. It isn't tested and i haven't used it in production, but it seems to work fine. It enables you to create an association on one end of the chain while not worrying about the other end. Like this:

    public class ClPerson : XPObject {
        #region Constructors

        public ClPerson() {
        }

        public ClPerson(Session session)
            : base(session) {
        }

        #endregion
       
        #region Fields

        private String m_name;
        private ClAddress m_addressMtO;

        #endregion

        #region Properties

        public String Name {
            get { return m_name; }
            set { m_name = value; }
        }

        #endregion    

        #region Associations

        [OneToMany, Association("AddressesOtM", typeof(ClAddress))]
        public XPCollection<ClAddress> AddressesOtM {
            get { return GetCollection<ClAddress>("AddressesOtM"); }
        }
       
        [ManyToMany, Association("AddressesMtM", typeof(ClAddress))]
        public XPCollection<ClAddress> AddressesMtM {
            get { return GetCollection<ClAddress>("AddressesMtM"); }
        }

        public ClAddress AddressesMtO {
            get { return m_addressMtO; }
            set { m_addressMtO = value; }
        }

        #endregion
    }

    public class ClAddress : XPObject {
        #region Constructors

        public ClAddress() {
        }

        public ClAddress(Session session)
            : base(session) {
        }

        #endregion

        #region Fields

        private String m_street;

        #endregion

        #region Properties

        public String Street {
            get { return m_street; }
            set { m_street = value; }
        }

        #endregion               
    }

You gonna have to assign the custom made IXReflectionDictionary when the program starts up like this: XpoDefault.Dictionary = new IXReflectionDictionary();

I've posted the code in this topic: http://community.devexpress.com/forums/p/65308/222111.aspx#222111

A sample is provided.