I have the same problem with my Table saw, which is just an ordinary circular saw mounted on a sub board, sharing my Router sub board mounting in the table.
My Router, (Trend T11EK) has a locking power switch, however the table saw does not.
I use a plastic cable tie to permanently hold down the on trigger button on the saw. (As suggested here by Harry).
I have left it loose enough to just slide off the trigger for conventional use of the saw, (If needed).
As with all rotating cutter tools, it is an essential safety feature, and I strongly urge the use of a Magnetic type No-Volt Switch, to prevent re-energising of power tools in the event of momentary power loss. (You can buy these on ebay for about $20-50, a small price to pay for the prevention of severe injury).
Last edited by HDS; 07-13-2009 at 05:41 AM.