OK. In fact, i am to buy an ADC-212/100 but currently, i am using a 3204, so i was testing PicoScope selecting ADC-212. As long as software was not able to find an actual ADC-212 device, maybe toolbars was configured for worst case (212/3), so ETS option was not available.
However, looking at programming reference for both 3200 and ADC-212 available in your web site, i could find API functions for dealing with ETS in 3200 (ps3000_set_ets() and ps3000_get_times_and_values()) while equivalent functions are missing in ADC-212 reference. Since ETS requieres critical timing in sampling hardware, i think it is not possible to implement ETS only in PicoScope software but, hardware support is needed. Maybe documentation is not up to date.
This is a link of programming guide found on your web site: "document/pdf/adc2xx.pdf". As you see, only one document is available for all ADC-2XX products.