Representing the present perfect continuous

Question

Given that the simple present tense in Esperanto can represent the present perfect progressive, given context (e.g. a simple "faras" in "mi ĝin faras ekde iam antaŭe" can mean "I have been doing it since sometime ago"), how can one emphasize the continuity?

An example sentence to illustrate my point can be something like this.

"I am not doing it [now], but I have been doing it! I swear!"

The following translation, using the above thing, sounds pretty weird.

"Mi ĝin nun ne faras, sed mi ĝin faras! Mi ĵuras!"

Sure, maybe I can use "esti faranta", but would most listeners notice my intended distinction? Or would it be lost in an often needless participle form?

"Mi ĝin nun ne faras, sed mi ĝin estas faranta! Mi ĵuras!"

My assumption is that it would be like in French, and perhaps an ekde (depuis) would be necessary to express continuity [since some past fojo].

"Mi ĝin nun ne faras, sed mi ĝin faras ekde <iam>! Mi ĵuras!"

Or, as someone else suggested, perhaps with a different order.

"Mi ĝin nun ne faras, sed ekde <iam> mi ĝin [ja] faras! Mi ĵuras!"

Kion sugestas vi?

Answer 1

The following seems intended, with stress on now.

Nun mi ne faras ĝin, sed mi estis faranta ĝin.

With estis-anta: i.o. the point-of-time estas-inta.

As there is a tendency to use simple tenses, the following might still be clear.

Nun mi ne faras ĝin, sed mi ja faris ĝin.

An other verb specifying a period might also be feasible. (When talking about text translation.)

Nun mi ne faras ĝin, sed mi jam okupis min pri ĝi.

Answer 2

Such a separation to progressive and perfect verbs is an aspect of English and some other languages. Thanks to Kazimierz Bein esti + aktivaj participoj have largely fallen out of use (and that is fine). Having said that you can emphasize with …estis faranta like Joop Eggen says, but save such forms for really emphasized use. More common is to express the idea by other means.

Mi ne faras ĝin ĝuste nun, sed mi ja faris ĝin/mi jam okupis min pri ĝi!