Problem with apply control records IDoc AAE

Hi Experts,

     I'm facing a problem with a receiver IDoc Communication Channel AAE:

    System specification:

          SAP PI 7.31 JAVA Stack only SP Stack Number 08.

     We are sending the following fields in the EDI_DC40:

  <MANDT>

  <DOCNUM>

  <DOCREL>

  <STATUS>

  <DIRECT>

  <OUTMOD>

  <IDOCTYP>

  <MESTYP>

  <SNDPOR>

  <SNDPRT>

  <SNDPRN>

  <RCVPOR>

  <RCVPRT>

  <RCVPRN>

  <CREDAT>

  <CRETIM>

  <SERIAL>

In this case the Idoc is HRMD_A07 without any extension, and we are not using any Partner Profile Function.

The configuration in the Receiver CC is the following:

Control Record in IDoc XML Mandatory (I try also with Not Mandatory)

Apply Control Records from Payload Checked.

The rest of the Advance Options unchecked.

The error inthe communication channel is this one:

Message processing failed. Cause: com.sap.aii.af.idoc.exception.IDOCAdapterException: Error during transform: java.lang.NullPointerException: while trying to invoke the method java.lang.String.length() of a null object loaded from local variable 'chars'

Seems that a mandatory field in the control record is missing but under my perspective all the mandatory fields are filled in the Message Mapping.

Thanks in advance for your support.