Hi,
Can you please tell if I can add the language sp? If so please tell me where I should place then.
Thank you

The easy way is to put a silent installer of the .net framework that already include the language pack in the hfsvcpack folder. Surely, someone has to make one. Otherwise, you can use a english one and then use a runonce command to install the language pack (maybe adding a proper cmd file in the hfguirunonce folder)

Thank you for replying
Can you provide me with an outline of the procedure you are suggesting to follow? I am using a english one but I am having some difficulties to applie the language sp

You could also just try Silent .NET Maker which supports language packs, and then put the resulting file(s) in either HFSVCPACK or HFGUIRUNONCE. Be advised that .NET 3.0 SP1 and .NET 3.5 can't be installed at T-13 so they should be placed in HFGUIRUNONCE.