The 2> log.txt works for me but the log lines seem to be truncated.
[2013-07-09 18:47:28] Stratum from pool 0 detected new block
[2013-07-09 18:47:28] Pool 0 stale share detected, submitting as user requested
[2013-07-09 18:47:28] Rejected 8bf7b43b Diff 34/32 GPU 0 pool 0 (SHARE SUBMIT: Job '188' not
[2013-07-09 18:47:36] Accepted 9afc3a16 Diff 94/32 GPU 0 pool 0
[2013-07-09 18:47:37] Accepted 29c58c31 Diff 674/32 GPU 1 pool 0
[2013-07-09 18:47:38] Accepted 7ef956e3 Diff 126/32 GPU 0 pool 0
[2013-07-09 18:47:38] Stratum from pool 0 detected new block
[2013-07-09 18:47:40] Accepted 88dbc164 Diff 93/32 GPU 1 pool 0
[2013-07-09 18:47:43] Stratum from pool 0 detected new block
[2013-07-09 18:47:47] Accepted 321881f0 Diff 107/32 GPU 1 pool 0
[2013-07-09 18:47:47] Accepted abf83337 Diff 33/32 GPU 1 pool 0
[2013-07-09 18:47:55] Rejected 461519c8 Diff 457/32 GPU 0 pool 0 ((1213, 'Deadlock found when
[2013-07-09 18:47:58] Stratum from pool 0 detected new block
[2013-07-09 18:47:59] Accepted ddfa7b85 Diff 39/32 GPU 1 pool 0