Right, heres's a more worked on work-in-progress. It fits the tune.

I'm not too sure of some of the words in the last verse, but the sense is there, I think:

On a dull grey empty morning, in the prison yard,
The wind it blows so cold, it is enough to freeze the heart.
But still somewhere there's sunshine, the sun is shining so warm
There on her tiny chair, my little Carlotta waits.
Mamma has promised "Cross my heart, Papa is coming home,
Some day he's coming home, he'll soon be coming home
And you'll be waiting here, so very very very good,
Keep watch for him, keep looking towards the camp."

So sitting on her balcony Carlotta's looking out
Is "Papa" coming soon, this man she's never met?
She's just a little worried, it is all a little much,
She chews her baby bottle, and gives a sigh.

"Who knows what he'll be like?
This so very famous man who married my Mamma
P'raps he'll have a beard, a chubby little man
A pipe, a cane, and glasses, dangling upon a cord

Who knows indeed? That rascally Papa…"

The sun's set on the city now, blue twilight's all around.
You'll not see him today, in prison he is bound.
The little eyes are drooping now, "Tomorrow he'll be here,
So, goodbye, baby bottle…" and she's asleep

The prison camp is silent, cold, it's useless, amd it's dead
The huts and towers are empty now, the guards they all have fled
And out there where there is sunshine, the sun is shining so warm
There on her tiny chair, little Carlotta waits.
Mamma has promised "Cross my heart, Papa is coming home,
Some day he's coming home, he'll soon be coming home
And you'll be waiting here, so very very very good,
Keep watch for him, keep looking towards the camp."

So sitting on her balcony Carlotta's looking out
Is "Papa" coming soon, this man she's never met?
She's just a little worried, it is all a little much,
She chews her baby bottle, and gives a sigh

"Who knows what he'll be like?
This so very famous man who married my Mamma
P'raps he'll have a beard, a chubby little man -
A pipe, a cane, and glasses, dangling upon a cord

Who knows indeed? That rascally Papa…"

And then around the corner comes a soldier from the war
A shining silver helmet, and on his breast a star
His tunic is bright blue, and all his buttons gleaming gold:
Papa is home. Papa has won the war.

As I was putting this together, I kept on remembering meeting my own father for the first time. (Well, I couldn't remember seeing him as a baby), when he came home from the war, and he came up the stairs and said hello.