Audriau, aren't you getting abit too familiar? You should address me as "Mr.President."
But getting back to my suggestion, I would like to point out that there exist examples of Soviet Lithuanian mail sent elsewhere - including South Africa (I have such an airmail cover sent in 1946 from Šiauliai to Johannesburg). Your card to Ecuador is interesting for two reasons: first, postal stationary sent registered was not that common in Lithuania (even during the independence period of 1918 - 1940). Second, lets see what the reverse of your card reveals! Now, now, lets not be shy.
After all, we're not playing philatelic hide and go seek. I'm 99% sure your card will reveal philatelic correspondance. Zenkevičius during WWII lived in Telšiai, and along with Mikulskis and Grigaliunas was buying up the 1941 Telšiai overprints in full sheets as they appeared in the post office. As for old Zenki (if memory serves me correctly he was a physician) I have a cover sent from the United States addressed to Zenkevičius in Klaipėda (if I remember correctly) in the late 1960s with an international T postage due marking in centimes. Aha - lets open up another can of worms. Philatelic correspondance with Lithuania including censorship and confiscation markings during the 50s and 60s. Now thats real FUN! (and if you wonder why I'm not showing anything - the reason is simple - I don't keep my collection at home.) Maybe someday I'll show some gems, but I want others to wet my whistle. At least you're trying Dr.B.!!!