Problem with receiving output channel from my STB

[bzamfir]

TV-Server Version:
MediaPortal Version: 0.2.3.0 latest SVN
MediaPortal Skin: Blue Two Wide
Windows Version: Win XP Pro SP2
CPU Type: AMD Sempron 3000+
HDD: Seagate 160 GB UATA, 320 GB SATA
Memory: 1.5 GB DDR400
Motherboard: ECS K8M800 - M2
Motherboard Chipset: K8M800 + VT8237R
Motherboard Bios:
Video Card: Forsa Nvidia Geforce 6200A 256 MB Ram
Video Card Driver:
Sound Card: Realtek AC 97' for VIA
Sound Card AC3:
Sound Card Driver:
1. TV Card: Hauppauge HVR 1300
1. TV Card Type: Analog + DVB-T
1. TV Card Driver: -
2. TV Card: -
2. TV Card Type: -
2. TV Card Driver: -
3. TV Card: -
3. TV Card Type: -
3. TV Card Driver: -
4. TV Card: -
4. TV Card Type: -
4. TV Card Driver: -
MPEG2 Video Codec: Nvidia PureVideo
MPEG2 Audio Codec: Nvidia PureVideo
Satelite/CableTV Provider: -
HTPC Case: Antec Fusion
Cooling: Hand-Tuned Arctic Cooler Freezer 64 Pro with Antec Fan with speed regulator
Power Supply: Antec
Remote: Girder + Universal learning remote
TV: Samsung LE26R41B
TV - HTPC Connection: DVI-HDMI

I have a STB General Instrument GT1900 (Scientific Atlanta)
My cable provider have some channels not encoded (which I receive directly with hauppauge HVR1300 TV tuner, and they are properly tuned in by MP, and some encoded, which are decoded by my STB. I use Hauppauge IR Blaster to change channels on STB, and I receive the encoded channels through the STB output RF channel, 7 in MP. On my TV, Samsung, the STP output channel is saw as C 2, 55 MHz
I setup MP to receive external channels through STB RF cable, by haching TVDatabase, ands setting the channel number (7) instead of the value for AV input (25000, etc)

The reason I don't use AV output from STB is I use AV to connect directly to my TV, as my wife and kids cannot use MP on a daily basis.

The problem is, sometimes after I apply a SVN, it seems the MP does not receive any signal on channel 7 (from STB). So if I change to a channel who is received decoded through STB, I get No Signal and nothing is received.
I tried to set the channel in MS config using the frequency (55) but still don't works.

This used to work sometimes back, but lately I could not manage to make it running again.

Can anyone help? It puzzles me, since all other RF channels, not encoded, are shown very well, and the channel received from STB should act exatly like the unencoded channels

Thanks

PS: to MP developers, maybe you can include in MP config directly the option to receive external channels through a RF channel, not only through AV / SVHS in, so we don't need to hack the tv database. Thanks