GetEventLog - how to have 'Message' property expanded in one line

n PowerShell v2 i'm using this cmdlet Get-EventLog Security | Export-csv C:\file.txt and get the following result.

I need to get all information in one line. In my sample the 'Message' property is multiline.

"538","MYPC","System.Byte[]","28330","Accesso/fine sess.","2","SuccessAudit","Fine sessione dell'utente:

    Nome utente:    myusername

    Dominio:        MYPC

    ID di accesso:  (0x0,0x58C702F)

    Tipo di accesso:    3
","Security","System.String[]","538","18/01/2013 10:35:54","18/01/2013 10:35:54","MYPC\myusername",,

I also tried with Format-Table but it truncate the Message field.