I found a solution:
public static void placeBlock() {
Minecraft mc = Minecraft.getMinecraft();
EntityPlayerSP player = mc.thePlayer;
if(player != null && player.getHeldItem() != null && player.getHeldItem().getItem() instanceof ItemBlock && mc.objectMouseOver != null && mc.objectMouseOver.typeOfHit == MovingObjectType.BLOCK) {
mc.playerController.func_178890_a(player, mc.theWorld, player.getHeldItem(), mc.objectMouseOver.getBlockPos(), mc.objectMouseOver.sideHit, mc.objectMouseOver.hitVec);
player.swingItem();
}
}