[Zope] acquisition syntax doubt

[ilflaminio@virgilio.it]

Hi all
I have two folder A e B in the root:
|_A (id=3DA title=3DA)
|_B (id=3DB title=3DB)
In B I have a dtml method "getTitle", with the line <dtml-var title>.
If I use the url /B/A/getTitle it returns 'A', and this is OK.
But if I have a method in the root with the line <dtml-var "B.A.getTitle(=
)">
I have a keyerror (title parameter). Why with the syntax B.A.getTitle()
the method getTitle() doesn't acquire by A?
Thanks.
Michele