Error obtaining data from session

Hello,
I have problem when I try to obtain data from session.
I have created .xpl pipe which use data from session, but there is problem when I try to call .xpl pipe from other .xpl pipe.
Namely, when I open that .xpl pipe (who use session data) directly from browser like:
  http://localhost:8080/orbeon/test1;
it return session data, but when I call it from other .xpl pipe with any processor like:
  <p:input name="config" href="http://localhost:8080/orbeon/niis/test1"/>;
I get null.

Is any Ideas how to solve this problem!?