You can write a script (see the about dialog for infomaion on how to integrate a script) or set the text in /apps/billboard/text (GConf).
signal sender=:1.1565 -> dest=(null destination) serial=108 path=/com/akozhan/fmradio; interface=com.akozhan.fmradio; member=rdsText string "KELLY CLARKSON - DARK SIDE - KELLY CLARKSON - DARK SIDE " signal sender=:1.1565 -> dest=(null destination) serial=109 path=/com/akozhan/fmradio; interface=com.akozhan.fmradio; member=stationName string "ZUERISEE" signal sender=:1.1565 -> dest=(null destination) serial=110 path=/com/akozhan/fmradio; interface=com.akozhan.fmradio; member=signalChanged uint32 10 boolean false signal sender=:1.1565 -> dest=(null destination) serial=111 path=/com/akozhan/fmradio; interface=com.akozhan.fmradio; member=stationName string "SIERISEE" signal sender=:1.1565 -> dest=(null destination) serial=112 path=/com/akozhan/fmradio; interface=com.akozhan.fmradio; member=stationName string "ZUERISEE" signal sender=:1.1565 -> dest=(null destination) serial=113 path=/com/akozhan/fmradio; interface=com.akozhan.fmradio; member=ptyInfo string "Children's programmes" signal sender=:1.1565 -> dest=(null destination) serial=114 path=/com/akozhan/fmradio; interface=com.akozhan.fmradio; member=ptyInfo string "Pop music"