In that fashion, at long last:
 Code:
Function IsNumeric($strInput)
  Dim $sc, $rc
  $sc = CreateObject("ScriptControl")
  $sc.Language = "VBScript"
  $rc=$sc.Eval('IsNumeric("'+$strInput+'")')
  If $rc = -1
    $IsNumeric = 1
  Else
    $IsNumeric = 0
  EndIf
EndFunction