Trouble getting weekday name in VB code

I want to use VB code for comparing TextContent, but I can't. If I run the following code I get an error stating that "Weekday is not declared", but according to VB tutorials I should be able to use it without a problem:

Dim todayDate As Date = Date.Now()
Dim dateToday As String = todayDate.ToString("yyyy/MM/dd")
Dim timeToday As String = todayDate.ToString("yyyy/MM/dd hh:mm")
Dim dayName As Integer
Dim dayNameShort As String

dayName = Weekday(todayDate)

Select Case dayName
     Case Is = 1
         dayNameShort = "Sun"
     Case Is = 2
         dayNameShort = "Mon"
     Case Is = 3
         dayNameShort = "Tue"
     Case Is = 4
         dayNameShort = "Wed"
     Case Is = 5
         dayNameShort = "Thu"
     Case Is = 6
         dayNameShort = "Fri"
     Case Is = 7
         dayNameShort = "Sat"
End Select

Pages.CashLedger.xDdTag.AssertContent().TextContent(ArtOfTest.Common.StringCompareType.StartsWith, dateToday & " 12:00 AM " & dayNameShort & " - " & timeToday)

Also when seeing the output of the code if I leave our Weekday, I see that date is not correctly formatted. Instead of defined "/" separator a "." is used, like:

OK - 04/07/2015

NOK - 04.07.2015 - this is what formatting in VB does in Test Studio!

Please help or point me to doc where such cases are already explained and can be done without a code.

Thanks, Jurij