I search for the error, and got here:
http://stackoverflow.com/questions/27205961/entity-type-has-no-key-defined-ef6
So you have 2 options it seems: (this is MVC scaffolding's requirements, and not a problem of our tooling, but I can imagine it's daunting what to do at this point)
1) add [Key] attributes to the PK fields (I'll describe how to do that below).
OR
2) Rename the PK fields so they match the pattern <classname> + Id
The second one seems pretty cumbersome, so I'll explain how to do 1).
I also would like to point you to some other things: In the project settings we have extensive features for Name construction. There you can define strip patterns to strip off 'Tbl' prefixes for example. See: http://www.llblgen.com/Documentation/5.0/Designer/Functionality%20Reference/ProjectSettings.htm#conventions-entity-model-element-name-construction and scroll down a bit under 'Name construction, Strip patterns'. It does require to recreate the project, but if you want to use better names, you can. You also don't have to suffix the names with 'Entity', the EF6 templates don't require that.
Anyway, to apply [Key] attributes to all entity PK fields, do the following.
1) Open the project, and then right-click the project node in project explorer and select 'Settings' to open the project settings
2) Navigate the left tree: Conventions -> Entity Model -> Code generation -> Attributes and click that node
3) On the right you can now select an element type. Select from the element type list 'Normal field'
4) In the grid below it, add a new row. For Attribute Definition, specify "Key" (without the quotes). Press TAB to go to the Has rule column and click '...' next to the 'no'.
5) The rule editor pops up. Click [+] to add a new rule. In the first combo box select 'Is part of PK'. In the second combo box select 'is true'. Click OK
6) You're now back in the attribute grid. Press enter to add the row to the grid. Then click OK to save the settings.
If you now edit an entity in its editor, and go to the code generation info tab and its Attributes sub tab, and select a field that's a PK field, you'll see the Key attribute is assigned to that field. If you select a non-PK field, you'll see the attribute isn't there.
This is now defined for all entities, and when you make changes the attributes are taken care of. So generating code will apply the [Key] attribute to the PK properties in the entity class.