Autocompletebox value not binded in radgrid

Hello,

I have a Gridview with a autocompletbox and other types of fields inside. The gridview is binded by Sql (SqlDataSource1) and all fields are populated in both Item and Insert mode without any problem, except the Autocompletebox.

The Autocompletebox works fine, meaning that it contains all the values from the SqlDataSource (SqlDataSource4 below) but the value that appears in the item mode (that uses SqlDataSource1) is not populated in editmode.

What is wrong with my code to retreave the SqlDataSource1 value? A codebehind is needed?

Thanks in advance.

<MasterTableView DataSourceID="SqlDataSource1" AutoGenerateColumns="False" DataKeyNames="FlowID" CommandItemDisplay="Top " ItemStyle-CssClass="grid">

                <Columns>
                    <telerik:GridBoundColumn DataField="BudgetCode" HeaderText="Budget" SortExpression="BudgetCode" UniqueName="BudgetCode" CurrentFilterFunction="Contains" AutoPostBackOnFilter="true" ShowFilterIcon="false" FilterControlWidth="80" HeaderStyle-Width="100"  ></telerik:GridBoundColumn>
                </Columns>
                <EditFormSettings EditFormType="Template">
                    <EditColumn ButtonType="ImageButton" />
                    <FormTemplate>
                                                <telerik:RadAutoCompleteBox ID="ddlBudgetCode" runat="server" DataSourceID="SqlDataSource4" DataTextField="BudgetCode" DataValueField="BudgetCodeId" InputType="Token">
                                                </telerik:RadAutoCompleteBox>
                    </FormTemplate>
                </EditFormSettings>
            </MasterTableView>