>I found the problem - we need to join on xType, not by Type to SysTypes
>

>declare @ProcID int
>Select @ProcID = OBJECT_ID from  sys.procedures P where p.Name = 'ap_NewWarehouse'
>
>SELECT syscolumns.Name AS ParamName, systypes.Name as DataType, syscolumns.length 
>	FROM syscolumns INNER JOIN systypes ON syscolumns.xtype = systypes.xtype where 
>	SysColumns.ID = @ProcID
>	Order by syscolumns.Name
>	
>

Much simpler version

Select  *   
   From   Information_Schema.Parameters   
   Where  Specific_Name = 'ap_NewWarehouse'