Hi
You should be able to cut and paste text in Czech into the subtitle option of VP. e.g. (Please excuse the translation...)

However I agree this is not the same as importing an srt file but at least this option seems to work here. For this test I translated a text line with Google (hence sorry for any errors :-)) and then copy/pasted that into the VP subtitle window where it appeared as shown in the image above.
To check if the font etc. was retained I then saved this subtitle as both an SRT file and an SSA file. Cleared VP and reloaded both file types with the same video. Both reloaded OK except that the SRT file needed to be reformated in size. The font (apparently) was fine. The test used the ARIAL font.
Nat