PSCustomObject to Hashtable
Shouldn't be too hard. Something like this should do the trick:
# Create a PSCustomObject (ironically using a hashtable)
$ht1 = @{ A = 'a'; B = 'b'; DateTime = Get-Date }
$theObject = new-object psobject -Property $ht1
# Convert the PSCustomObject back to a hashtable
$ht2 = @{}
$theObject.psobject.properties | Foreach { $ht2[$_.Name] = $_.Value }
Keith already gave you the answer, this is just another way of doing the same with a one-liner:
$psobject.psobject.properties | foreach -begin {$h=@{}} -process {$h."$($_.Name)" = $_.Value} -end {$h}