Flex 4 Combo - Using IME

I am trying to use ime (for hiragana login) in flex 4 flex combo. Upon completion, I install the following.

cbx_text.textInput.imeMode = IMEConversionMode.JAPANESE_HIRAGANA;

And check by tracking the following:

trace(cbx_text.textInput.enableIME); returns true;
trace(cbx_text.textInput.imeMode); returns JAPANESE_HIRAGANA;

However, when I select text input and start typing, I cannot switch to hiragana.

I can configure it to work with the textinput component without problems.

<s:TextInput imeMode="JAPANESE_HIRAGANA"></s:TextInput>

Does anyone have any experience? Any insight is greatly appreciated.