Sorry about the long delay in replying to this.

To answer your questions (as well as I can):

1. You dont neccessarily need a ProjectInstaller - its mainly used to
create the initial EI.config file.
I'll put a snippet out of another thread at the bottom of this reply that
explains more about the installers in EIF.

2. EIF is looking in the current working directory of the running process.
I expect that the BizTalk process is picking up your orchestration and
executing it with a current working directory of "C:\Program
Files\Microsoft Biztalk 2004". If you can figure out what process is
actually running your orchestration you can put an entry into its .config
file to tell EIF to look in another directory. See the topic "Selecting
Configuration File Location" in the EIF help (i.e.
EnterpriseInstrumentation.chm)

3. I guess you'd have to use interop but I really dont know if it will work
or not. Methinks probably not.

Hope this helps

Mike

==============================
Here's a bigger explaination of all the EIF installers from the thread
in this newsgroup "EIF - InstallUtil what exactly does it do?"
-----------

There's actually three installutils in EIF:
1) installutil-ing the instrumented app
2) installutil-ing the schema dll.
3) some installutil-ing goes on when you first install EIF.

1) installutil-ing the instrumented app
---------------------------------------------------

Yes, you can hand craft the EI.config file and not perform the installutil
on the instrumented application. The only action missing would be the
registration of the EventSources in the Windows Event Log (specifically no
calls to System.Diagnostics.EventLog.CreateEventSource() are made).

It should be noted that the LogEventSink will automatically call
EventLog.CreateEventSource() if needed when the instrumented application is
executed. The only problem is that sometimes apps (e.g. ASP.NET Web Apps)
dont have sufficient permissions to make this call. In this case, the
logEventSink fails to load for this EventSource, an error is output the
Windows Event Log (notifiying of the error) and events that would have been
output to the logEventSink are dropped.

2) installutil-ing the schema dll.
---------------------------------------------------

This second one performs the following actions:
a) checks that all the event Types are of valid structure (e.g. EIF doesnt
allow self reference cycles - such as a typical node in a linked list
structure)
b) delegates through to WMI.NET's
System.Management.Instrumentation.ManagementInstaller - This Installer
registers the structure of the events in WMI's CIM Repoisitory and allows
the events to be output through WMI.NET

3) some installutil-ing goes on when you install EIF.
---------------------------------------------------

I wont go into much detail here, but a quick summary:
a) The perf counter categories and counter names are setup.
b) The Windows Trace Session Manager (TSM) service is installed.
c) The TraceRequestStart/EndEvent (or something like that name) are
registered with WMI's repository.

--------------------