[TYPO3-calendar] Display country value instead of label

[TYPO3]

Dear List,

I want to display country value using country marker, ###COUNTRY###, for 
example United Kingdom will only shows "GB" which is this the
value of select option,

<option value="GB">United Kingdom</option>

I already set the country code to: ISO 3166-1 A2. Is it possible to 
shows value instead of label?

Thanks in advance.

Dodi