Did Soulja Boy Really Write Willow Smith's "Whip My Hair"?

...or is he just getting a paunchy publishing check for his one-liner? Though the 20-year-old cocksure rapper tweeted the below yesterday:
 
A quick google search credits Janae Rockwell and Ronald "Jukebox" Jackson for penning the spunktacular hit. We're not mad at SB for feeling himself, but lying to yourself would be another story. So did Souljer really get his ghostwrite on or is he supersoaked in bs?