Output from external exe and my custom objects in powershell

(Sorry for strange title, haven't come up with anything better..)

Background

I use nunit-console to test my assemblies. It is called like this (simplified):

function Test-ByNunit {
    param($assembly, $tempFile = 'c:\temp\nunit.xml')
    & <path-to-nunit-console> $assembly /nologo /xml:$tempFile @othparam 
}
Test-ByNunit c:\temp\myAssembly.dll

I have no problem with this, it works fine.

Problem

nunit-console should output its messages as so far. That means - if not captured, it should send them to screen, otherwise it could be stored in file (Test-ByNunit $dll | set-content path)

I'd like to return somehow information about each test-case that was run (the info is stored in the /xml file) in form of array of PSObject objects.

Question

Do you have any tip how to return the info and still leave nunit output its messages?
If I simply write it to output, the function will return array of strings (output from nunit-console) and array of my objects. Then redirection to output file will store my objects as well, but I'd like just display them in console window.

The only possibility that could work is to use [ref], but I'd like to avoid it.

(this is not only about nunit-console, but of course it is general question)

If I got the task right then Out-Host should help:

function Get-WithOutHost {
    # external output is redirected to the host
    cmd /c dir | Out-Host
    # normal output to be reused later
    Get-Process
}

# call    
$result = Get-WithOutHost

# now $result holds the data to use, external output is on the screen

EDIT: of course this is not enough if external output should be reused, too, not just shown