The question is more crucial than it seems.
Ehud Olmert and the ruling Kadima party is only in power under the legal fiction that he is serving as a temporary replacement for Ariel Sharon. Of course Sharon is not going to go back to being Prime Minister but as long as he's lying in the hospital with occasional health updates, the fiction is maintained, however poorly. Should Sharon actually be buried though, the legal fiction would take on entirely new realms of twisting the law.
Olmert and Kadima's problem is that their entire existance and power is based on Sharon. To remain in power they need Sharon in the hospital, but after a few days of constant health updates the public tunes out. Like every form of entertainment, a media circus needs something new to top it. Succeeding surgeries on Sharon didn't do it. Olmert's administration has been a disaster and now with the sentencing of Sharon's son, one of Kadima's top figures and an MK, Olmert and Kadima very badly need the distraction and circus of the funeral of a Prime Minister. Reproducing the circus of the Rabin funeral and memorials before the election would provide Olmert with a stage to ramble on about Sharon's legacy and pass himself off as the inheritor to that legacy.
The irony is that Sharon's funeral is badly needed to give Olmert and Kadima legitimacy but at the same time a funeral would dispose of their legal legitimacy to be in power. Look for the funeral to be scheduled very close to election time when Olmert and Kadima stand to benefit the most and when it is too late for any legal petitions to remove Olmert from power.