Modify existing Indicator to an Signal-Indicator with Buy/Sell Arrows

I have the "allaverages" indicator. the goal is to modify this indicator to a signal-indicator with arrows for long an short.

the new indicator should have all settings from this "allaverages" indicator. this mean, i should can predefine which MA indi should take. the modification is,
that i should have an upper and lower band on it.
if i set for example a SMA with Period 20, Indi should set an upper and lower band on this MA with a predefined xPips distance.
the second part to generate the signal is, that indi should have (with all paramaters from the allmovingaverages indicator) a second MA.
The signal arrow should generate if the upper/lower band from first MA cross the second MA.
That Mean:

for long; if MA (second MA) cross from up to down the lower band (first MA) => Blue Arrow up
for short: if MA (second MA) cross from down to up the upper band (fist MA) => Red Arrow down