I also could install svox classic, but not the voice packs. After some research i found the solution! First, copy the apk of the voice (in my case the dutch voice of Lena, i bought it for my htc desire phone, and made a backup of the apk.) Copy this backed up apk to a map in your t1 (i used data/data). I used rootexplorer for this.
Then, unmount the SD card in your reader(just go to the settings of you rooted t1 and unmount the sd card).
Then, use rootexplorer again to install the apk, located in data/data. Now it installs fine!
Dont forget to mount your sd-card again! Afterwards I used Link2SD to move the app to my SD card. (i had to shut down the device once and restart it, because Link2SD didn't work anymore..) Then you go to settings - text-to-speech settings and make svox your default engine. After doing this, still in your text-to-speech setings, you have to configure SVOX and make the program download your voice-data (if everything goes well, it is going to download all the data to your sd-card (make sure your WIFI is on! It's about 19MB) Now you can use it with Coolreader or FBreader. On my HTC Desire it works better than on my Sony t1, but, thats probably because the processor in the t1 is weaker. The voice sometimes stutters a bit, but it's usable and a lot better than the standard Pico-tts engine.