Forms Data Controls :: Populating DropDownList Inside A ListView Inside A FormView

I have the following (abbreviated) code:

<asp:FormView ID="FormView1" runat="server" DataKeyNames="ItemID" DataSourceID="LinqDataSource1">
<EditItemTemplate>
<asp:DropDownList ID="ddlCategory" runat="server" SelectedValue='<%# Eval("Category") %>'
DataSource="<%# GetCategories() %>" DataTextField="Text" DataValueField="Value" />
</EditItemTemplate>
<ItemTemplate>
<asp:ListView ID="lvParticipants" runat="server" DataSource='<%# Eval("Participants") %>' >
<InsertItemTemplate>
<asp:DropDownList ID="ddlCountry" runat="server" SelectedValue='<%# Eval("Country") %>'
DataSource="<%# GetCountries() %>" DataTextField="Text" DataValueField="Value" />
</InsertItemTemplate>
</asp:ListView>
<ItemTemplate>
</asp:FormView>

When the FormView is in Edit mode, ddlCategory is populated as expected by calling GetCategories(), which returns a List of categories. However, when the ListView is in Insert mode, ddlCountry is empty. I put a break point in GetCountries(), but it never gets called. If I change the name of the method, I get an error. So it recognizes the method at compile time, but does not call it at run time. I'm guessing this is an embedded binding issue of some kind, but I'm hoping someone can save me a lot of time by pointing out the solution.