WatiN unable to find textbox by id nor name

I have been beating my head in the wall all evening on this, can someone give me some idea how I can get WatiN to TypeText into this text box? It is disabled until a radio button is selected and I am at a loss.. I am still a bit new to all of this to go easy on me

<TR>
    <TD WIDTH="100">Billing ID</TD>
    <TD nowrap>
        <INPUT TYPE="radio" NAME="reg_type" VALUE="Biller" ONCLICK="disableSubmitter(); clearAll(); document.config_frmV_f5a46cc226670cb3a4d7e0f5a98703a0.vendor_ID.disabled=false;">
        <B>Vendor ID:</B>
    </TD>
    <TD WIDTH="100"><INPUT TYPE="textbox" SIZE="10" NAME="vendor_I开发者_如何学GoD" ID="vendor_ID" DISABLED ONBLUR='setupAjax();' value=""></TD>
</TR>
<TR>
    <TD>Submitter ID</TD>
    <TD nowrap>
        <INPUT TYPE="radio" NAME="reg_type" VALUE="Submitter" ONCLICK="disableBiller(); clearAll(); document.config_frmV_f5a46cc226670cb3a4d7e0f5a98703a0.existing_Billing_ID.disabled=false;">
        <B>Billing ID:</B>
    </TD>
    <TD WIDTH="100">
        <INPUT TYPE="textbox" SIZE="10" NAME="existing_Billing_ID" ID="existing_Billing_ID" DISABLED ONBLUR='setupAjax();' value=""></TD>
    <TD><INPUT TYPE="hidden" NAME="ff_option" VALUE="N"></TD>
</TR>

Here is the JavaScript for the onblur command to enable the textbox

function setupAjax()
{
    var sendStr = "";

    if(document.config_frmV_f5a46cc226670cb3a4d7e0f5a98703a0.reg_type[1].checked && document.config_frmV_f5a46cc226670cb3a4d7e0f5a98703a0.vendor_ID.value.length > 0)
    {
        document.config_frmV_f5a46cc226670cb3a4d7e0f5a98703a0.existing_Billing_ID.value = "";
        sendStr += 'reset=false&vendor_ID=' + document.config_frmV_f5a46cc226670cb3a4d7e0f5a98703a0.vendor_ID.value;
        sendStr += '&existing_Billing_ID=';

    }
    else if (document.config_frmV_f5a46cc226670cb3a4d7e0f5a98703a0.reg_type[2].checked && document.config_frmV_f5a46cc226670cb3a4d7e0f5a98703a0.existing_Billing_ID.value.length > 0)
    {
        document.config_frmV_f5a46cc226670cb3a4d7e0f5a98703a0.vendor_ID.value = "";
        sendStr += 'reset=false&existing_Billing_ID=' + document.config_frmV_f5a46cc226670cb3a4d7e0f5a98703a0.existing_Billing_ID.value;
        sendStr += '&vendor_ID=';
    }
    else 
    {
        return;
    }

I have tried to select by Id, Name, Index, you name it and I still cannot populate it despite the fact I can touch every other element on the page.. I am able to find it using the Element and it will report back the name however I cannot figure out how to populate the box using Elements

Figured a work around out for the problem by using JavaScript, working like a charm now!

         StringBuilder js = new StringBuilder();
            js.Append(@"var myTextField = document.getElementById('vendor_ID');");
            js.Append(@"myTextField.setAttribute('value', '201153');");
            ie.RunScript(js.ToString());

Question: Are you trying to enter a value in the textfield while it is disabled?

You won't (or at least shouldn't) be able to do something like mybrowser.TextField("myFieldID").TypeText("words go here") until the TextField is enabled.

Pseudocode

1. Click the radio button
2. Wait for the textfield to become enabled
3. Type text in the textfield