Hi,
here are some buttons to control iTunes playback...
Previous Song
<?xml version="1.0"?>
<button backcol="none" display="both" textcol="none">
<label>iTunes: Previous Song</label>
<icon1>#player_rew</icon1>
<function type="normal">
<instruction>YOURPATH\iTunesControl.exe PREV</instruction>
</function>
</button>
Pause
<?xml version="1.0"?>
<button backcol="none" display="both" textcol="none">
<label>iTunes: Pause</label>
<icon1>#player_pause</icon1>
<function type="normal">
<instruction>YOURPATH\iTunesControl.exe PAUSE</instruction>
</function>
</button>
Play
<?xml version="1.0"?>
<button backcol="none" display="both" textcol="none">
<label>iTunes: Play</label>
<icon1>#player_play</icon1>
<function type="normal">
<instruction>YOURPATH\iTunesControl.exe PLAY</instruction>
</function>
</button>
Stop
<?xml version="1.0"?>
<button backcol="none" display="both" textcol="none">
<label>iTunes: Stop</label>
<icon1>#player_stop</icon1>
<function type="normal">
<instruction>YOURPATH\iTunesControl.exe STOP</instruction>
</function>
</button>
Next Song
<?xml version="1.0"?>
<button backcol="none" display="both" textcol="none">
<label>iTunes: Next Song</label>
<icon1>#player_end1</icon1>
<function type="normal">
<instruction>YOURPATH\iTunesControl.exe NEXT</instruction>
</function>
</button>
I used icons from the Crystal Project OPUS MOD v0.3 -actions-, but feel free to change them to your liking 
Those buttons base on a small executable I created to access the COM-Object of iTunes. The attachment of this post contains the AutoIt3-Sourcecode as well as compiled x86/x64-Exes. Just place the appropriate EXE whereever you like and fix the paths "YOURPATH" in the button-codes respectively.
Have fun! 
iTunesControl.zip (664 KB)