Miriam, I don't think there are any other Odia speakers here except me:) I think the virtual keyboard is a blunder and it doesn't have the feature to combine alphabets like you mentioned a combined letter. But I think we have another alternative to that, we can use the symbols which are fortunately present in the keyboard. For example,ନମସ୍କାର, we can write it like this-ନମସ୍କାର. Ohh no! I got it how to write. I think the keyboard is not that bad we thought it is! Just use this symbol" ୍" after ସ. Thanks for asking this question. I could discover it because of you:)