RichText Textalignment (cocos2dx v3.9, c++)

Hello Friends,

could somone pls tell me how I can change text formation in a cocos2d::ui::RichText Widget?
I want to set horizontal textalignment to “center”. and vertical textalignment to “middle”.

this kind of text formatting is possible in cocos2d::ui::Text Widgets but it seems to be not implemented in RichText Widgets???

Would be nice to get a hint