[pstricks] trees: putting objects on tree branches

[MA V]

Hi--
I'm currently using PStricks for drawing tree diagrams but there are two things that I haven't figured out how to do yet.

Just for explanation purposes, suppose I have the tree: http://tug.org/PSTricks/pst-tree/tree7.tex
What I would like to do is the following:
1) Between nodes 0 and 10, add a triangle (on top of the line connecting the two nodes; i.e. the line would be interrupted by the triangle) and write something on the right side of that triangle.
2) Draw a cross on top  of the connection between nodes 1 and 4.

How can I do this?
Any suggestions are appreciated.
Thanks!
Ana
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