why can't my swf call/use the android virtual keyboard?

I have a Flex 4.5.1 swf web app that works a treat on a Galaxy S2 except that the virtual keyboard won't appear.

( Android 2.3  Flash player 10.2 and 10.3 tested ). I think I've covered all bases - see below.

<s:TextInput id="userNameText" text=""  x="145" y="155"  styleName="LoginText"

height="55" width="420" change="userNameText_changeHandler(event)"  needsSoftKeyboard="true"

focusIn="{this.requestSoftKeyboard()}" />

Even when a button rams the call for the keyboard it still doesn't dock:

<s:Button label="go V K" x="700" y="400" click="{userNameText.requestSoftKeyboard()}" width="200" height="200" />