Style is lost in conversion to RH8 from an older version

We had all help files created in an older version of RH, went through the conversion process, but for all the topics we have not yet (or do not need to open except for this problem), the stylesheet formatting is not applied to the topic. (For example, all fonts remain Times Roman black when they should be Arial). We can fix this problem by going into each one and editing, then rebuilding, but that will take hours. Any suggestions?