CustomValidator Embedding inside DataList SelectedItemTemplate

My goal is to call the call the CustomAcctNumValidate procedure I wrote from a CustomValidator located inside a the SelectedItemTemplate of my DataList. The Textbox that is being validated is also in the SelectedItemTemplate of my DataList.
 
Code (I know this can be done with RangeValidator, but its a test for something else):
 
HTML:
<asp:CustomValidator id="cvAccountNum" runat="server" ErrorMessage="Account Number Must Be Less Than 25 Characters" OnServerValidate="CustomAcctNumValidate" ControlToValidate="txtAcctNum_SelItem"></asp:CustomValidator>
 
VB.NET Code Behind:
Sub CustomAcctNumValidate(ByVal source As Object, ByVal args As System.Web.UI.WebControls.ServerValidateEventArgs) Handles cvAccountNum.ServerValidate
If args.Value.Length > 25 Then

args.IsValid = False

Else

args.IsValid = True

End If

End Sub

The error is on the cvAccountNum object in the Handles clause:  "Handles clause requres a WithEvents variable"

Declaring a WithEvents variable breaks the CustomValidator.

Any Suggestions?