clickTag with URL Parameters

I have these 2 functions in a Flash file banner:

ON THE TEXT BOX
on (keyPress("<ENTER>")) {
    getURL("http://www.domain.com/Landing.aspx?source=41","_blank","POST");
}

AND ON THE BUTTON
on (release) {
    getURL("http://www.domain.com/Landing.aspx?source=41", "_blank");
}

Inside the file, the text box is phone and it passes phone along with the url, like this:
http://www.domain.com/Landing.aspx?source=41&phone=VALUEFROMTEXTBOX

Now, I need to add clickTag for advertisers to track the clicks? How can I code the function to send the url (http://www.domain.com/Landing.aspx?source=41) and the parameter &phone=VALUEFROMTEXTBOX

I have tried this and it doesn't work:

on (keyPress("<ENTER>")) {
    getURL(clickTag add "&phone=" add phone);
}

That appends &phone to the end of the current URL.

Thank you in advance.