What I did is I downloaded the angular front end over at Userapp. Tried to copy the index.html to work in Webflow tools. I hosted the java script files on my server and linked them inside Webflow. Linked bootstrap as well just to get it to work easy. I used custom attributes on the body on every page that needs it <body ng-show="myApp">. The partials in the downloaded files i used html embeds to get them in webflow. For the inputs webflow can be used with custom attributes but not for the form itself for what I can see, It needs an directive and I don´t know how to do that inside webflow, I want to use custom attributes but I must fill the value there.
Could perhaps @cyberdave be some help here or pass along to the team so this could be doable, remove restriction on having a value in custom attributes? =)