I don't get any search results!

I just installed Acronis True Image Home 2011 on my windows7 PC. I did an ordinary backup (*.tib file, non encrypted).

Step1
Now I want to search for a specific file within my backup. Therefore I type a file name (e.g. *.jpg) into the search field at the very top right of the program window. And nothing happens. I repeat this. Up to now I never got any result.

In step 2
I double-click on my tib file and see my folders and files in windows explorer. Great! I type into the search field but windows explorer does not find anything neither.

What is wrong?