i wanted to write an away message, can someone tell me if this is correct?

Mi ne estas cxi tie, sed je mia reveno, mi redonos vian mesagxon.

I'm not here, but upon my return, I will return your message.

would this also be correct:

Mi ne estas cxi tie, sed kiam mi revenas, mi redonos vian mesagxon.

I'm not here, but when I come back, I will return your message.

also, in the second one, can i use "kiam mi estis reveninta"?

Mi ne estas ĉi tie, sed je mia reveno, mi redonos vian mesaĝon.

Use "respondos" instead of "redonos" and you're good. (redoni = to give back/to give again)

Mi ne estas ĉi tie, sed kiam mi revenas, mi redonos vian mesaĝon.

I would use "kiam mi revenos", but it just might be because of my mother tongue, which would use the future tense for both verbs.

also, in the second one, can i use "kiam mi estis reveninta"?

"kiam mi estos reveninta". But it would be far too much detail for such a sentence.

waxle:

mnlg:

s.hofius:Mi ne estas cxi tie, sed kiam mi revenas, mi redonos vian mesagxon.

I would use :kiam mi revenos", but it just might be because of my mother tongue, which would use the future tense for both verbs.

Well, here I definitely disagree (on the usage issue, not the cause). "...cxi tie, sed kiam mi revenas..." is actually leaving out a word; it would more completely be "...cxi tie, sed tiam, kiam me revenas...". As I understand it, in that case, the sentence is referencing the time at which the present tense is true, though the future tense might be correct at the moment of speech.

According to PMEG 33.4.3, the "tiam" in "tiam, kiam" can be (and usually is) left out unless it's needed for clarity or emphasis. As to the tense, "revenos" is right (33.2.7, see also 33.8.1). You might be confusing indirect speech with other subphrases:

Kiam mi revenos, mi respondos.
Mi respondos, ke mi revenis.

waxle:You know, I might disagree.

Feel free to. In 10+ years of written and spoken Esperanto, in a few different styles, I have found compound verb tenses extremely unfrequently. Yes, it's more precise (and I am glad there are ways to be more accurate if you have to), but you won't need it for casual usage.

mnlg:Well, here I definitely disagree (on the usage issue, not the cause). "...ĉi tie, sed kiam mi revenas..." is actually leaving out a word; it would more completely be "...ĉi tie, sed tiam, kiam me revenas...".

Yes, it would be more canonical, but it is also correct to leave it out, AFAIK.

"Mi ne scias kion vi volas" can be used for "Mi ne scias tion, kion vi volas".

Feel free to look around for proof. I'd be glad to know what you find. Who knows, I might have been wrong for all this time...

thanks for the feedback, the first one is really what i was going for, and that's the one that seems to be most correct except for the one incorrect word... the rest of it is just my brain trying to figure out how else it could be said... as for revenas vs. revenos, i'm not quite sure, the way i think of it (thinking in english) is: "when i do return" (revenas) and "when i will return" (revenos) and it seems like either would work fine (... in english)

(sorry about the poor formatting and excessive use of '...')

s.hofius:as for revenas vs. revenos, i'm not quite sure, the way i think of it (thinking in english) is: "when i do return" (revenas) and "when i will return" (revenos) and it seems like either would work fine (... in english)

In English one doesn't use "will", but in Esperanto one does, because it will happen in the future.