PMS + sony bravia TV + yellow subtitles + .MP4

[mrtnspaul]

Dear,

computer specs: Core 2 Duo 2.33 GHz, 8 Gb DDR2, Windows 7 SP1 x64.
version of PMS: 1.54 (Build 37c80caa1)
streaming to: Bravia TV NX series. I dont use the PS3 to streaming. I'm not using a custom renderer profile.
network setup: PC <-> D-Link DI-524 Router <-100mbps-> SONY Bravia TV (DLNA)
Engine in use: MEncoder
streaming problem:

Files MP4 do not get the yellow subtitles, even adjusting, they just turns white. Why?
For the USB input of the TV, it recognizes only MP4 files.
Files Avi and MKV work OK.

What configuration change?

More...
Some videos are in 1080p and are not full screen on TV, but they're with 1920x816 resolution. How to put full screen?

Thank you.