* FY net profit up 17 pct to $632 mln vs $636 mln forecast * Company guides for "good growth" in 2013 * Analysts disappointed by lack of quantitative target * Shares down 3.3 pct By Sarah Young LONDON, Feb 27 (Reuters) - British oil services firm Petrofac just missed 2012 profit forecasts and failed to give a specific target for this year, spooking investors already unnerved by a rivals' shock profit warning.