Have you made your ibus setup work with other front-ends or other applications prior to this?
The way DriveLine works, it registers hotkeys globally within windows. Even if the keys are not sent specifically to DriveLine, it should still pick them up.
The hotkeys that DriveLine registers are:
CTRL+M to toggle mute
CTRL+Plus to increase volume (in 10% increments)
CTRL+Minus to decrease volume (in 10% increments)
CTRL+RightArrow for Next
CTRL+LeftArrow for Prev
CTRL+H for HomeScreen
CTRL+S to cycle through media sources.
I'm not familiar with ibus, but my suggestions are:
Send me the ini and I will take a look at it.
Try sending your keys to "Explorer"
Try sending your keys to "DriveLine_InvisibleForm"
It could be an issue with the way you're specifying the 'CTRL' part of the key command.
It sounds like ibus is using 'SendKeys'. I don't know if the hotkeys registered in DriveLine will pick these up as actual keyboard presses.
Have you tested the functionality within DriveLine using just a regular keyboard?