Re: FileMAsk
You are in PowerShell, you have full "power" of that language:
$lastMonth = (Get-Date).AddMonths(-1)
$firstDayOfLastMonth =
Get-Date -Year $lastMonth.Year -Month $lastMonth.Month -Day 1
$timestamp = $firstDayOfLastMonth.ToString("yyyy-MM-dd")
$filemask = "*>=" + $timestamp
$transferOptions.FileMask = $filemask