I attempted many stabs in the dark trying to get a very old pre flash 8 version of a swf working (w IE7) and believe I have found something that will cover the "_self" case. After setting window.location.href with IE7 and escaping the double quotes as shown below I was only then able to successfully get this to work:

args = "?parm1=value";
baseURL ="http://mydomain.com";
getURL("javascript:window.location.href=\"" + baseURL + "MyServletName" + args + "\";");