sending a variable to a javascript pop up from flash

[ladida]

When a flash button is pushed, I am trying to use javascript to open a new window and pass a variable on using "POST". The new window opens, but the variable is not passed. I know the problem is in the flash, because if I take away the javascript and just open the link in a "_blank" target, it works fine and the variable is passed. (But then I cannot control the size and other attributes of the new window)

Here is the code I am using:

on (release) {
getURL("javascript:MM_openBrWindow('thankyoudefault.asp',' thankyou','scrollbars=yes,resizable=yes,width=200, height=300');", "_self", "POST");
}

Any ideas??? Do I need to send the variable separately? How?

Note: I tried setting the target to "_blank" and "thankyou" and it caused the popup to not work display correctly.

Thanks in advance!!!!