You should be able to convert LVF to MKV (actually remux LVF to MKV) using gdsmux from Haali Media Splitter

My gdsmux resides in the following folder
c:\Program Files\Matroska Pack\haali\gdsmux.exe


Alternatively you can try to use GraphEdit:
1. Launch GraphEdt.exe
2. Select Haali Media Splitter and choose LVF file
3. Select Haali Matroska Muxer and select the output .MKV file
4. Connect audio and video pins, and hit the Start