I am pretty sure those texts are in the locale files.
There was a similar request for changing the
"I will call you later" text for the reject call message.
http://talk.maemo.org/showthread.php?t=80587

you have to find the appropriate locale file
in /usr/share/l10n/meegotouch directory.
Copy the file to your desktop and use qt linguist to
open and change the text.
(But I don't know in which, if at all, file you'll find
the text).

Nicolai