showColumns with subTable columns in Reporting API

Using the http API I have

  ...?module=API&method=Live.getLastVisitsDetails&idSite=1&period=month&date=today
&format=JSON&&showColumns=idVisit,visitorId,userId,dimension1,actions...

actionDetails is a nested object that I would like to only include a few columns from.

Does anybody know if there is a way to include only specific nested columns from a subtable / nested object using showColumns. e.g. for actionDetails, I tried

``` etc, but no joy.

Thanks

any update ?
i’m facing the question