xlsx files in test case

Hi everyone,

I have problem with copying excel file xlsx in test case in Test Management (SOLMAN). I already solved problem with MIME Type according to Note 1062725, but when try copy document I get error message (see figure below).

MIME type settings:

I tried insert new excel documents xlsx again a generate new test plan. We have newest Solution Manager 7.1 SP8 with updated central notes. I tried compare problem in other Solution Managers (SP 05, SP 06) and it is still same. 

Could you anybody help me please?

Thx, by