Hitting ENTER key in AJAX ComboBox not shifting focus to textbox

See more:

ASP.NET

Ajax

combobox

I am having the foll0wing issue with this....

This is my scenario:
- Using AJAX ComboBox
- Set AutoComplete to Append
- Set AutoPostBack to True
- Set DropDownStyle to DropDownList

What I am trying to do:
I have a combobox with a list of employees which upon typing the first few letters of the name and when I HIT ENTER not SELECT the name, I would like the employee info to update in my Formview. This works fine if I SELECT the name, however not when I hit Enter.

In doing some research I have come to learn that Tabbing out of the combobox will cause the SelectedIndexChanged procedure to fire, which is fine by me, HOWEVER, I cannot get the act of hitting the ENTER key to mimic the act of hitting the TAB key.

This is what i have tried and it does not work

VB Code
Page Load

Me.ComboBox_Guest.Attributes.Add("onkeydown", "return SetNextControlFocus(event,'" + TextBox1.ClientID + "')")

ASP
Script

function SetNextControlFocus(e, controlclientid) {

        var evt = e ? e : window.event;
        var ctrl = document.getElementById(controlclientid);

        if (ctrl) {
            if (evt.keyCode == 9) {
                ctrl.focus();
                return false;
            }
            else {
                if (evt.keyCode == 13) {
                    ctrl.focus();
                    return false;
                }
                else {
                    return true;
                }
            }
        }
        else {
            return true;
        }
    }

Your assistance is greatly appreciated