Debug issue in HANA Studio

Hello, i've created stored procedure with some input and output parameters. There is one input DATE parameter there. When i declare it as NVARCHAR(10) debug is ok, but i'm facing a problem of comparison with other dates. So i decided to declare that parameter as DATE:

CREATE PROCEDURE xxx(

  IN bukrs NVARCHAR(4),

  IN dat DATE, [...]

When i'm trying to debug this procedure i get the next error message:

Error while executing XXX.

IN or OUT param is missing at position 1

Here is my input parameters:

And once again, when i declare dat as NVARCHAR(10) there is no  trouble with debugger.

Any ideas? Thanks is advance.