Thanks! I followed the instructions and yes, I can ping myself and the pings appear in the comments of the corresponding post.
And another yes: It was possible to send a Trackback from the Testblog to my blog and again the Trackback appeared in my comments. So receiving doesn’t seem to be a problem.
But sending trackbacks seems to be more difficult. I tried two different blogs, one wordpress-blog and one based on a different software. I used the trackback-URIs but my trackbacks didn’t appear in their comments. So what could be the problem with that, since it was possible to ping myself after all?