[TYPO3-english] Newsletter distribution via Cronjob - Missing Salutation

[Chris]

Hi Guys

we have an error with sending the newsletter via cronjob: The marker 
###USER_tx_gender### is not displayed in the newsletter.
Only the last name (###last_name###) is displayed correctly, e.g. "Meier".

Though by sending the newsletter manually via " Invoke Mailer Engine" 
everything is displayed correctly, e.g. "Sehr geehrter Herr Meier".

We are using Typo3 4.4.4
direct_mail 2.6.9
(We have entered "gender,las_name" in the "addRecipFields" of 
direct_mail in the extension manager.)
df_direct_mail_subscription 1.0.5

In our newsletter template the markers are named as follows:
###USER_tx_gender### ###USER_last_name###

We have already changed the backend language english/german. But it 
didn't help neither.

Do you know what we are doing wrong?

Thank you in advance
Best Regards
Chris