EA from .ex5 ?
Yes its possible if the indicator provides buffers, You can see if indicator is providing buffers using Data window
If buffer exists it can be read by iCustom
If indicator creates objects then its also possible by reading Objects
If indicator provides Alert or Prints anything then its also possible to create EA by reading the Log file for any new prints.
If indicator does not provide buffers, alert, prints or objects then its not possible to read indicator calculations and make EA.