Adding command-line argument to Windows Service when installing using WiX

I managed to create a WiX 3.x installer for Windows Service and added some standard UI.

While installing Windows Service using WiX I need to add a command-line argument to that Windows Service. That argument is a path to config.xml file. And I want to give user an option to browse for that config.xml file through "Browse..." option. I think I need a 开发者_开发问答CustomAction for that but how would it look like?

Thanks so much in advance.

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Perhaps this will help: http://community.saasgrid.com/developers/b/team/archive/2011/02/17/wix-managed-custom-actions-openfiledialog-example.aspx