Android numeric keypad - how do I enter a negative decimal value?

[refaQtor]

I've discovered that some versions/brands of Android provide a numeric keypad without the ability to enter negative and/or decimal values. So, I added Qt.ImhFormattedNumbersOnly to my inputMethodHints: property. This produced a keypad with a button that has both a decimal and minus on a single key. I can't seem to get the single key to give me the minus. I tried holding the key longer, hoping to get the key to cycle through the options - no luck.

Any ideas how to address this?