Problems while connecting google-calendar AND Exchange-calendar in Lightning

I connected a google- and an MS Exchange-Account into TB - and it worked really well. But when it comes to connect calendar(s) of both accounts I gained some trouble: I installed the following add-ons to get it done: “Lightning 4.0.2”, “Exchange EWS Provider 3.4.0~beta7” and “provider for google calendar 1.0.4.”. After this I connected the Exchange-Calendar to TB - everything worked really fine. After that I tried to connect the google-calendar and that doesn’t work at all: At first I was asked for the “xml-adress” (not the Googlemail-Account!) and after filling in and confirming the process stopped?!

I found out that you have to install the add-ons in a specific order: At first you have to install “provider for google calendar 1.0.4” and connect the calendars of your google-account. And the second step must be the installation of “Exchange EWS Provider 3.4.0~beta7” and the connection of the “Exchange”-Calendar(s).

I don’t know if the problem is originated from one or both add-ons? For me it worked right now perfectly - but who knows what happens after the next update?!

Did anyone have the same experience? Is there another / better possibility to connect the calendars of an exchange- and a google-account to TB and Lightning?

best regards