No stratification is needed.
>is there any trick for stimulating the germination.
I just sow on the surface of finely milled peat and keep very moist. I
cover mine with a plastic top to keep humidity very high. But watch
out for damping off. If you see a very fine mold starting to grow on
the surface of the peat, spray the peat with a mister full of rain
water. For me this seems to knock the mold down and kill it, at least
for a while. Repeat as necessary.
>How long takes it to germinate?
Mine come up in 4 to 5 weeks and people think (after a couple of
months) that the "little darlings" are sooooo cute :)
Good luck,
John Walker