  Adatom incorporation into the ``faceted'' steps bordering the 2D nanoislands
is analyzed. The step permeability and incorporation coefficients are derived
for some typical growth situations. It is shown that the step consisting of
equivalent straight segments can be permeable even in the case of fast egde
migration if there exist factors delaying creation of new kinks. The step
consisting of alternating rough and straight segments may be permeable if there
is no adatom transport between neighboring segments through the corner
diffusion.
