Black screen, do you have this issue? (1 Viewer)

[atlantic]

MediaPortal Version: MP 1.1.3
MediaPortal Skin: Streamed MP
Windows Version: Seven 64b sp1
CPU Type: Amd Athlon II x2 245
HDD: Samsung 1To
Memory: 2go ddr3
Motherboard: Gigabyte MA785GMT-UD2H
Video Card: Sapphi HD5450
Video Card Driver: Catalyst 10.2
Sound Card: realteak (Motherboard)
Sound Card AC3: hdmi out
Sound Card Driver:
1. TV Card: Hauppage USB Wintv mini st
1. TV Card Type: dvb-t
1. TV Card Driver: the last
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: ffdshow tryout
MPEG2 Audio Codec: ffdshow tryout
h.264 Video Codec: ffdshow tryout
Satelite/CableTV Provider:
HTPC Case: 3Rsystem HT1100
Cooling: fan
Power Supply: Seasonic II 380w
Remote: Logitech Harmony One
TV: Sony Kdl40w5500
TV - HTPC Connection: hdmi

Hi guys,
My system is : htpc linked to my a/v receiver, itself linked to my tv by hdmi.
Here is my problem.
Imagine that a recording is started. I want to watch the begining of this recording. So I switch on my tv and my A/V receiver.
Problem: the tv screen remains black and my A/V receiver displays "no hdmi signal".
If I use my remote controle ("ok", "move up, down, right, left"...) , there is no change. (it's a soundgraph device)
But, if I use my keyboard , I press "enter", "move right...", the tv screen is reactivate.

Do you have the same issue?
Thanks