Passing empty cells to sql-server shows "0" instead of NULL - sql-server

Question

I'm passing values from excel to sql-server via stored procedure.
There are two columns in excel in wich the cells contain integers or are empty.
But in sql-server, the empty cells from one column are shown as NULL, and the empty cells from the other are shown as "0". Why is that? Both variables are declared as integers in vba, and in sql.
What do I have to do to get everywhere NULL if the cell is empty?
This is part of the vba-code:
Dim rst As New ADODB.Recordset
Dim cmd As ADODB.Command
Dim query As String
Global ktghnev As String
Global ktghID As Integer
Dim elsosor As Integer
Dim pt, bank As Integer
Dim fizmod As String
Dim honap As String
With ActiveSheet
elsosor = 3
Do Until .Cells(elsosor, 1) = ""
nevID = .Cells(elsosor, 1)
pt = .Cells(elsosor, 4)
bank = .Cells(elsosor, 5)
If IsEmpty(Range("D" & elsosor)) = False Or IsEmpty(Range("E" & elsosor)) = False Then
Set cmd = New ADODB.Command
cmd.ActiveConnection = cnn
cmd.CommandType = adCmdStoredProc
cmd.CommandText = "EURfeltoltes"
cmd.Parameters.Append cmd.CreateParameter("#nevID", adInteger, adParamInput, , nevID)
cmd.Parameters.Append cmd.CreateParameter("#ktghID", adInteger, adParamInput, , ktghID)
cmd.Parameters.Append cmd.CreateParameter("#honap", adVarChar, adParamInput, 10, honap)
cmd.Parameters.Append cmd.CreateParameter("#pt", adInteger, adParamInput, , pt)
cmd.Parameters.Append cmd.CreateParameter("#bank", adInteger, adParamInput, , bank)
cmd.Execute
End If
elsosor = elsosor + 1
Loop
End With
This is the stored procedure:
ALTER PROCEDURE [dbo].[EURfeltoltes]
#nevID int = null,
#ktghID int = null,
#honap nvarchar(10) = null,
#pt int = null,
#bank int = null
AS
BEGIN
SET NOCOUNT ON;
insert into bertabla (nevID, ktghelyID, honap, eurpt, eurbank) values (#nevID, #ktghID, #honap, #pt, #bank)
END