If Send-MailMessage is a problem try "[System.Web.Mail.SmtpMail]::Send($mail)"
Here is a script I wrote using the above command to send email using Gmail
$SendingServer = "smtp.gmail.com"
$FromAddress = "******@gmail.com"
$ToAddress = "******@gmail.com"
$SmtpPort = "465"
$GmailPass = Get-Content "c:\agmail.txt" | ConvertTo-SecureString
$Cred_Gmail = New-Object System.Management.Automation.PsCredential($FromAddress,$GmailPass)
$subject = "checking the connection"
$body = "this is awesome"
# Create a new mail with the appropriate server settigns
[System.Reflection.Assembly]::LoadWithPartialName("System.Web") > $null
$mail = New-Object System.Web.Mail.MailMessage
$mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpserver", $SendingServer)
$mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpserverport", $SmtpPort)
$mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpaccountname", $FromAddress)
$mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpemailaddress", $FromAddress)
$mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate", 1)
$mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendusername", $FromAddress)
$mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendpassword", $Cred_Gmail.GetNetworkCredential().password)
$mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpusessl", $true)
$mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendusing", 2)
$mail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpconnectiontimeout", 20)
# Set up the mail message fields
$mail.From = $FromAddress
$mail.To = $ToAddress
$mail.Subject = $subject
$mail.Body = $body
[System.Web.Mail.SmtpMail]::Send($mail)