Ok so you want a timer with fixed leading 0s if necessary and with significant figures up to centiseconds (1/100 of a second).
The timer gives the time in seconds in decimal format, with more sig figs than you need. So you'll need to round to the nearest centisecond - round(100*Timer). Then use the text object's APPEND action to add each digit you need, in addition to modulo which you seem to already know how to use.
Start with setting a variable with the total current time in centiseconds
Set text to (how many 10 minutes do I have? 10 minutes = 60,000 centiseconds, can be 0), subtract that from your variable
Append text (how many minutes are left? 1 minute = 6,000 centiseconds), subtract that from variable
Append ":"
Append (10 seconds=1,000 centiseconds), subtract from variable
Append (1 second = 100 centiseconds), subtract...
Append ":"
Append (10 centiseconds), subtract..
Append (whatever is left)
Hmm made sense when I wrote it, but now I look back and it might be kinda confusing. I can put together a capx later if you have trouble.
Edit: Looks like I didn't need modulo after all. Or maybe it will look cleaner if it is used? Or something... https://www.dropbox.com/s/w8ni4mmfom94b ... .capx?dl=0