How to remove Secure Store Application in SharePoint 2010 through Powershell?

Question

Although I have added the SharePoint snapin, "Add-PsSnapin Microsoft.SharePoint.PowerShell", I still get errors when delete SPSecurityStoreService as below descripted.

BCS: Message: The term 'Remove–SPSecureStoreApplication' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again.

Code section is as below:

$targetApplicationName = 'HRSST'   
$serviceContextUrl = "http://mingle.cnblogs.com:8080" #SharePoint server admin center
$ssApp = Get-SPSecureStoreApplication –ServiceContext $defaultServiceContext –Name $targetApplicationName
Add-PSSnapin Microsoft.SharePoint.PowerShell -EA SilentlyContinue 
[System.Threading.Thread]::Sleep(10000)
if ($ssApp -ne $null) 
{ 
     Remove–SPSecureStoreApplication -Identity $ssApp -Confirm:$false
 }