Looking at the Su-30 and Su-35 introduction to service, that can be a very slow process. In both cases, the air force has its predecessor (Su-27 and Su-24) in large numbers in service. Although outdated and mostly analogue systems, an upgrade is more economical than replacing them. Full rate production of the Su-34 will probably not start until after 2010, when the Su-24 airframes are starting to show their age. Some sources report the five aircraft as being an order from the Air Force, I am not sure, it wouldn't be the first time production started without orders in place. The air force staff is convinced of the Su-34 as its future tactical bomber, it is probably very wise move of NAPO to keep the development moving, to keep it in the light, also for export/marketing purposes.
The Chinese president visited Novosibirsk for economic/trade talks with the region, on the trip he visited NAPO factory, partly because Mao Zedong was there 55 years ago, but also to look at the Su-34, though he was more interested in the An-38 assembled there.