Possible to add custom designer for a class?

[Julia]

Hi

1.I am writing an addin to VS.NET and I would like to select class from the
class view explorer
and than, instead of the code, display a UML diagram for example.
is it possible to add a custom "designer"(is this the correct name?) for
class?

Basically I would like to see in VS.NET's tab the following
(assuming my class name is Person)

[Person.cs][Person.vsd]

2.Is it possible to add a custom file to the project and run a custom
compilation steps on it?
for example I want to add a file with suffix ".VTR"
and run my own compiler on it,the error and warning should be displayed in
VS.NET
Thanks in advance.