MANIS -we dont use it so often in Latvian,i dont think You should stress about it. :)
e.g. come to me -Naac pie MANIS (double AA means long a,i just dont have Latvian...sorry).
do you miss me? VAI TEV MANIS PIETRUUKST? or VAI ES TEV PIETRUUKSTU?
so it means you CAN choose,to use it or not in some cases...
i am not here -ES TE NEESMU or MANIS TE NAV

I agree with Lizzy. There are some possibilities, just is it exchange or... Try Google, if not, maybe i can ask some friends who knows?!

Hmm... I have no Tildes birojs on my computer and i just added Latvian keyboard. At the bottom of the screen where is clock, date, there is thelanguage bar. When i click with right button of the mouse, i get settings and right there i just add it. If you know how to use Latvian keyboard, won't be hard :)
If you manage to do that, let me know or just ask me...