[Rd] xtable formatting: RED for negative numbers?

I've been experimenting recently with the fantastic Sweave/xtable combination for generating latex. In the xtable vignette, I found this great example of printing a ts object by months. Is there a way to modify this code to generate RED numbers inside xtable for negative results in x.ts? Thanks

[Rd] BUG in RODBC() on Ubuntu 64amd : rows_at_time=1024

R 2.8.1 Ubuntu 64amd RODBC 1.2-5 - This was a hard-to-track bug for me, because sqlQuery() did not fail - instead, it looked like it returned some good data and some NA where there should have been numbers and 0 where there should have been NAs. I did: (a) sqlQu