I only need to have a crossing of EMA 8 and RSI 8 at the same window in order to see the cross.
It is very complicated to add it to ferextester?
Thank You very much
An EMA (Exponential Moving Average) is a filtered price curve, but an RSI (Relative Strength Index) is a derived oscillator. They won't work together in the same window since they are on vastly different scales.
For instance, the price of the GBPUSD might vary between 1.0 and 3.0 over a very long time. At the same time, the RSI of that pair would vary between 0 and 100, so the crossings would only occur at the very bottom of the lowest swings of the RSI (extreme oversold condition). I don't think that's what you're looking for.
Actually, such a thing already exists, as the Fozzy indicator (designed for use with a system of the same name being discussed on either www.forexfactory.com or www.forex-tsd.com, I can't remember which..). It gives an RSI, and MA of that RSI, and also Bollinger Bands of that RSI, all in one window. You can find it here: http://forextester.com/forum/viewtopic.php?t=776
If you set the MA Type to EMA, and set buffer colors 2, 3 and 4 to Transparent, it should give you just what you need...