This is another article that discusses this issue. Basically what they are saying is that while soft tissue usually degrades in a certain number of years, in some cases , under some conditions it does not.
Bottom line: Soft tissue in fossils do not prove that the fossilization happened quickly, it just means that tissue does not degrade quickly in certain environments.
http://rationalwiki.org/wiki/Soft_tissue_preservation
The common thread in this claim is the great irony of creationists dogmatically adhering to the results of lab studies using uniformitarianpreconceptions of processes lasting millions of years which nobody has directly observed.