Changing combobox filter text programmatically

Hello everyone, sorry for my poor english.

I have developed a virtual keyboard (client-side gwt component) for my vaadin application for ATM.
It work nice with textfields, but I need it to work with comboboxes.
Comboboxes filled from container with two properties: BigDecimal ‘id’
and String ‘name’, ‘name’ is used for combobox caption, ‘id’ as combo’s value for business-logic.

Of course, i can’t use combobox.setValue() with text from my keyboard.
How can i set typed on virtual keyboard text (‘name’ property) to combobox to trigger suggestion process?

Thank you for any advice.

Hello again. I chose other way and faced a new problem with ComboBox.
How can i focus combobox’s inner input field from javascript from jsni method ?
With TextField i use $doc.getElementById(fieldName).focus(); , with DateField $doc.getElementById(fieldName).getElementsByTagName("input")[0] .focus(); , it works fine, components become focused, and then i call native function (keyboard events generator) $wnd.wp.sendChar(character); and character appears in TextField ( or DateField), and and so on, as long as I do not change ‘fieldName’ (this value i set with setDebugId() on server side).
When i try send focus to ComboBox (similarly as with DateField), nothing happens.

PS: Vaadin 6.7.9