Given the runaround

I just bought a new mobile outright (K800i) from an Optus store near work. I am a Vodafone customer and wanted to remove the crappy Optus logo and pics from my phone, so...
I called Optus and they tell me to call Sony Ericsson, so....
I call Sony Ericsson and the guy there tells me that because the phone was branded for Optus, they cannot remove the logo. I argued that surely it was just software that could be removed and he said it wasn't, then I kept at him and he finally admitted that yes, it is removable BUT if I was to do so, it would void my warranty
I find this just ridiculous! Has anyone had this problem before and what are the solutions??
I called Optus and they tell me to call Sony Ericsson, so....
I call Sony Ericsson and the guy there tells me that because the phone was branded for Optus, they cannot remove the logo. I argued that surely it was just software that could be removed and he said it wasn't, then I kept at him and he finally admitted that yes, it is removable BUT if I was to do so, it would void my warranty

I find this just ridiculous! Has anyone had this problem before and what are the solutions??