Streamline - how to update data in the handle?

Hi everyone. I've got the following code:

h1 = streamline(streamdata{1})

for i =2:length(streamdata{i})

UPDATE "h1" WITH THE DATA FROM STREAMDATA{i}

pause(0.1) end

where streamdata is in the form XY, just as you can find in streamline help. Now I would like to use set(h1,Properties...) to update the streamline in my plot. Does anyone knows what property do I have to update?

Thank you!