How to :
Download exe and put it somewhere in PC, run it , it will automatic add registry path of application and add menu , icon to .XAP files
Then just close it and now double click to custom ringtones , or any .xap format files , the Tom XAP installer will automatic open and give you some details ( App name , Version , Author , Size , Description of XAP ) then select where you will install xap ( device or emulator )
Press Install and wait it finish.