Your plugin requires the "Compose message" plugin when one wants to add the button "Send message" to the hint. Why?

Oxwall already has the "Send private message" function on every profile, which could be used.

I understand, that the "Compose message" plugin is yours (and needs to be purchased) but it also needs to have the receiver typed in again... So it's quite complicated and not of real help. Using the inbuilt "Send private message" function would be much more comfortable and easier - though it means less revenues for you... ;)