<$button message="tm-new-tiddler" param="TaskTemplate">New Task</$button>works fine, adds the formatted text to the new tiddler.
With
But I couldn't find out how to combine them...Works fine too, creates a new tiddler with the title<$button> <$action-sendmessage $message="tm-new-tiddler" title="This is newly created tiddler" tags="OneTag [[Another Tag]]" text=<<now "Today is DDth, MMM YYYY">>/> New Tiddler </$button>"This is newly created tiddler", with thetags "OneTag" & "Another Tag" and the text "Today is 11.02.2018".
Writing the text into the 2. method doesn't bring the wanted result, because there are <div style, transclusions and other commandos in it.