Hello João ...

you can use this tip:
draw retangles in the report designer where your
chekbox are showen when the field value = 1(sorry for my english)...
then you might use the WingDings TTF Font for show the graphic character for the checkboX, with 24 of FontSize.

1.Double click in the charter "X", in the dialog boX chose "Print When"
as sayed Hilmar...
2.Chose "Print only when the..."
3.in the texbox type : myFieldName = 1

Ready!! only when your Field Value is=1 the Checkbox Character as showed...
Copy this character to de rest of rectangles draweds...

Tip
i use the Windows Charmap program to view the code for the ChekboX character
in win Xp the character is ALT+0xFB
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