Sure. Simply use a text animator for opacity and animate it to match the path offset/ rotation. Pre-compose if and when necessary...
Create a new comp the height of your text string and the same width as your main comp.
Add your long text string and don't worry that if may extend beyond the comp boundaries. Animate the position of the text layer so that it crosses the screen.
In a new composition import the text comp and apply CC Cylinder twice. Put the layer you want to obscure the text between the two instances of CC Cylinder and set one to render inside and one to render outside.
All Done. EZ as pie.
I guess it's never too late to say 'thank you' :-) Believe it or not, I still have this thread opened in one of my FF tabs all since then - as the reminder I have to reply!! :-) It is now exactly 2 years from when I got the answers so it is a pretty suitable moment to finally say:
Thank you to both of you for answering me - the answers helped me to make a nice Xmas card for the year 2014. :-)
And merry Xmas & a happy New Year!