Setting the flower pot content

I am doing a plugin and I need to set the flower pot content to an acacia sapling (data = 12). I have googled it and i found some people that use setContent, some people use setTypeIdAndData and replace it but these don't work for me. I am actually using 1.8.8 and this is my code, it practically replace the flower pot with air and after 5 ticks it should replace the air with a flower pot containing an acacia sapling.
This is my code:

Code:

loc.getBlock().setType(Material.AIR);
                               Bukkit.getScheduler().scheduleSyncDelayedTask(plugin, new Runnable() {
                                @SuppressWarnings("deprecation")
                                public void run() {    ;
                                       loc.getBlock().setTypeIdAndData(140, (byte) 12, false);
                                   }
                            }, 5);  

There aren't errors but it just replace air with an empty flower pot after 5 ticks, not as i want.
I can see the flower pot disappear and reappear really quickly but it's still empty.
Please help me doing this.
Thanks.
Sorry for my bad English.

 

@timtower Doent's work, same result.

 

@zioGiok
Have you tried using the "setContent" method?