Not sure if its the right key or not, done by ear, it's close enough for me.

Main riff
         1/2
E|--------------------------------|
B|--------------------------------|
G|--------------------------------|
D|-------3b-----------------------|
A|-0h3h4---5-4p3p0-3-5------------|
E|--------------------------------|
A variation
         1/2
E|--------------------------------|
B|--------------------------------|
G|--------------------------------|
D|-------3b-----------------------|
A|-0h3h4---5-4p3p0-2-1------------|
E|--------------------------------|
Another variation
         1/2
E|--------------------------------|
B|--------------------------------|
G|--------------------------------|
D|-------5b-----------------------|
A|-0h3h4---5-4p3p0-3-5------------|
E|--------------------------------|

this is all i've figured out, hope its good, and if not, hope it gives you a basis
on which to figure it out yourself on.
Thanks.