Created attachment 7234 [details]
original file

I need to convert adobe illustrator files to png and I lost the transparency of part of the image 
The gs command executed is: 
gs -q -dQUIET -dSAFER -dBATCH -dNOPAUSE -dNOPROMPT -dMaxBitmap=500000000 
-dAlignToPixels=0 -dGridFitTT=2 "-sDEVICE=pngalpha" -dTextAlphaBits=4 
-dGraphicsAlphaBits=4 "-r72x72"  "-sOutputFile=test.png" -ftest.ai 

I attach the test file here: test.ai 

And the result: test.png 

The result I should have (made using photoshop): test-ps.png

As you can see, the whole image should be transparent. 

The version 8.71, 9.00 and 9.01 give me the same results.