Relative Strength vs. the SP-500 is a very important indicator in determining the strength of a stock (whether its going with or against the market) and when to buy or sell it.  If you cannot create an automated custom formula to plot it as an indicator, then you should update or patch Telechart to include it as one of your standard indicators.

I strongly suggest that you update or patch Telechart to include Relative Srength vs. SP-500 as one of your standard indicators.