Need help implementing a [CACHEBUSTER] macro

I have been asked to incorporate a 1x1 tracking pixel. Because this is two different 3rd party APIs, I have to implement the 1x1 tracking pixel, inside my Flash files.

The SWFs 3rd party API has a method for using 1x1 tracking pixels

// Import URLHandler class
import PointRollAPI.core.URLHandler;
 
// Execute a beacon call to track the impression 
URLHandler.beacon("http://servedby.************/?cachebuster=[CACHEBUSTER]");

The 3rd party whose tracking pixel this is says this about their tracking pixels

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[TD]Notes to publisher:
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[TD]To ensure accurate tracking it is essential that you replace [CACHEBUSTER] in the tracking pixel tag with a random number or timestamp.

The only thing I am finding when I google is some documentation from DoubleClick, which is unfortunately not the #rd party API I am dealing with.

Any suggestions of what to prsue much appreciated.
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