Hi Yambo,
I have discussed with abstrax about this issue and I have to say that I was wrong.
The black dots are a consequence of a fix added in SDK v3.03.4 to solve this issue described here:
viewtopic.php?f=30&t=55903
Look at this example:

- v3.03.3

- v3.03.3

- v3.03.3 in Photoshop
with previous versions there is no artifacts but when composed, you have a white halo.

- v3.03.4

- v3.03.4

- v3.03.4 in Photoshop
with v3.03.4 you have some artifacts on borders, but the final composed result is correct.
ciao beppe