Step 1:
Goto this URL and click on the RADAR location you would like to display
http://www.bom.gov.au/australia/radar/
Step 2:
Look at the URL you have been taken to, it will look something like this
http://www.bom.gov.au/products/IDR023.loop.shtml#skip
Note the ID - see bold section it will start with IDR then is usually followed by a three digit number.
Step 3:
Open a new sign creator document, double click the background and set the dimensions to 562 wide and 564 height.
Step 4:
Choose Insert in the top menu, then choose Online picture
Step 5:
Type this URL in http://www.bom.gov.au/radar/IDR022.gif
Replacing the IDR022 with the IDR id from the URL in step 2 then click OK.
Step 6:
Double click the image, then under the image tab, add this after the URL, be careful not to add any spaces.
?rand=[year][month][daynum][24hr][min]
Then change the "Reload image every" to at least 120 seconds.
Step 7:
Go to the "General" tab.
Change the x and y coordinates both to 0
Then change the width to be 562 and the height to be 564
Click Ok.
Step 8:
Save the sign creator file, then add to your playlist as normal.