Outlook and MAPI GetMessage

[Simon]

Hi,

I'm trying to geta message thats stored in a public folder, but I get
the error:

[MAPI -[MAPI_E_INVALID_ENTRYID(80040107)]]

I'm programming this in c# creating a com addin for outlook.

What I need to do is find out the URL used to access the email through
the outlook web access. I found an artical saying that we need to find
the field PR_URL_COMP_NAME.

The only way to access this is by using MAPI, so I need to find the
message and store it in a MAPI.Message, to access this field.

Am I making any sense?

Thank you in advance,

Simon