Here's a toned-down translation; toned-down because copying the style of the English original would sound way too affected in German nowadays, to be used only if you were, say, a countess or suchlike.
kf, please wait until our Forum Legend, Faltrad, comes up with a better solution. Although other EFers sometimes don't appreciate it, he usually is right, so it may be worth the wait.
The 2nd case seems to be intended as an alternate phrasing, i.e. also an invitation. But to me it sounds more like an announcement, simply because the explicit invitation is missing.