Opening protected Excel files with ADO.NET

[PROPAR]

Hello,
The KB211378 warns that it's impossible to open a protected Excel file even in a readonly mode with ADO.NET.
This KB211378 sounds silly enough to me, since as I know the password I should be able to READ it !
The workaround is either
1/ to remove manually the protection password (@?#!!)
or
2/ to manually open the file with "Excel The Tool" and thereafter connect to it using ADO.NET (double @?#!!).

Neither option is satisfying so I have a few questions :
- is it possible to remove Excel password protection by program, and then re-protect the file afterward ?
- is it possible to open the Excel file in a silent mode (no desktop) just to trick Excel and ADO.NET read while it is open ?
- is there anything I can use to read the file other than ADO.NET ?

Thank you for sharing your knowledge with me.