hello!
well few things:
i got my logitech internet keyboard together with ati rw and it works with wa2 using key messages - there's part from players.ini in itouch's directory (itouch is driver / utility sw for logitech keyboards)
#List of supported players
#{btn|key|msg|emg|cmd|wac},exeName,wndClass,wndCaption,xxx,play_delayplay,pause,stop,prev,next,remove_flags,ShowOSD,menu_item
[Players]
MSPlain=btn,cdplayer.exe,SJE_CdPlayerClass,xxx,xxx,1000,1001,1002,1003,1006,0,1,Windows CD-Player
MSDeluxe=btn,deluxecd.exe,MMFRAME_MAIN,xxx,xxx,104,104,105,109,110,0,1,Windows Deluxe CD-Player
WinAmp=key,winamp.exe,Winamp v1.x,xxx,xxx,X,C,V,Z,B,0,1,WinAmp
WinAmp3=key,studio.exe,STUDIO,xxx,xxx,X,C,V,Z,B,0,1,WinAmp 3
Sonique=key,sonique.exe,Sonique Window Class,xxx,xxx,X,C,V,Z,B,0,1,Sonique
MSMedia=key,xxx,MPlayer,xxx,xxx,0x10,0x10,0x13,0,0,0,1,Windows Media Player
MSMedia2=key,xxx,Media Player 2,xxx,xxx,0x20,0x20,.,0x8021,0x8022,0,1,Windows Media Player
MSMedia7=wac,wmplayer.exe,WMP Skin Host,Windows Media Player,xxx,xxx,xxx,xxx,xxx,xxx,0,1,Windows Media Player 7
MSMediaX=wac,mplayer2.exe,WMP Skin Host,Windows Media Player,xxx,xxx,xxx,xxx,xxx,xxx,0,1,Windows Media Player
CineMaster=cin,dvdplayer.exe,AfxFrameOrView42,QI Remote Control,xxx,12,15,16,11,13,0,1,Cine Master
CineMaster2=btn,dvdplayer.exe,#32770,xxx,xxx,1014,1020,1029,1022,1028,0,1,Cine Master
Virtuosa=cmd,xxx,VirtuosaWndClass,xxx,xxx,0x8046,0x8045,0x8044,0x8040,0x8041,0,0,Virtuosa
MediaMatics=msg,xxx,xxx,xxx,xxx,7033,7036,7039,7035,7037,0,1,Media Matics
Axialis=btn,AXCDPLay.exe,AXCDPlayer20Class,xxx,xxx,112,113,114,115,116,0,1,Axialis
Axialis25=btn,AXCDPLay.exe,AXCDPlayer25Class,xxx,xxx,112,113,114,115,116,0,1,Axialis
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as you can see, it doesn't use normal winamp's messages to control it but instead those key messages. the line for wa3 has been added by me, i have just changed window class to STUDIO and executable name to studio.exe .... otherwise it's the same, so i guess you could use just the original code and change class name to STUDIO and probably check executable name for studio.exe because i don't think STUDIO class is best possible choice to identify wa3 (they should have chosen something more distinct).
and you send those messages directly to the app, it's the same message windows would send if the app would be in focus and you would press the key - and no, it doesn't send this message to active app etc
as for the cursor keys ... just try for yourself ... you wouldn't send that message for constant increase but let wa handle that ... you would just send message that cursor key 'left' has been pressed and is down etc ... it would make using remote for controling volume and seeking in a song much better, because it wouldn't 'jump'
well just give it a try and you won't be disappointed