Check out my blog post that basically shows how to implement this:

http://world.episerver.com/Blogs/Linus-Ekstrom/Dates/2012/11/Creating-a-more-advanced-property-editor/

Thanks. I will look into it.

I made your example work now after hours of cursing.... :)

Turned out that the objects you return from the rest service need to have a name and an id, not a name and value. Big thanks to Tomas Eld who wrote that in the comments.

Also, I must say this approach was really hard. I would never have solved this without your blog post. Is there any good resources that explains more how Dojo is used in Episerver 7 or something? How is one supposed to know that you need a new config file and 3 javascript files that define a lot of external files/namespaces, both dojo/dijit but also epi stuff.

For instance, what is 

"epi/dependency",
"epi/epi",
"epi/shell/widget/_ValueRequiredMixin"

and how should i know that I need them? Is there any documentation about this?

Anyway, thanks again!

Hi!

First of all, I updated the blog post to use Id. I guess that this might have changed in the 7.1 upgrade since we upgraded to Dojo 1.8 in that release.

Regarding documentation about how to work with expanding the UI, there exists some documentation, although we still lack a lot of information and samples, specifically for the EPi client API. The information that exists today is:

Information about the user interface in general, for instance an introduction to Dojo and further referenses to get started:

http://world.episerver.com/en/Documentation/EPiServer-Framework/?id=66798&epslanguage=en&version=7

Client Side API-documentation for CMS:

http://world.episerver.com/Documentation/Javascript-Library/?version=7.1&product=cms

Client Side API-documentation for the Framework parts:

http://world.episerver.com/Documentation/Javascript-Library/?product=episerverframework&version=7.1

Me and some other people have also written blog posts about this, for instance:

http://world.episerver.com/Blogs/Linus-Ekstrom/Dates/2012/10/Extending-the-User-Interface-of-EPiServer-7/

Regarding future improvements, we are currently working on improving the format and content for the client API documentation. I also hope that we will create a separate UI-project for CMS where we can put some common functionality to be able to implement common scenarios without having to write any client code at all. More info to come about this when we get closer to the next major release...

We actually use 7 and not 7.1, but we will soon upgrade. I guess some stuff might break then :)

Thanks for the links!