CANADA STOCKS-TSX helped by Ukraine and China; Canexus weighs

* TSX up 49.94 points, or 0.32 percent, at 15,669.02 * Index hits another record high on global cues * Couche-Tard bounces on unit sale; legal action hurts Canexus * Eight of the 10 main sectors gain (Adds strategist comment, updates prices to close) By Alastair Sharp TORONTO, Sept 3 (Reuters) - Canada's main stock index notched a broad but shallow rise on Wednesday, boosted by news of a ceasefire agreement between Ukraine and Russia and a rebound in Chinese economic data.