You have access to a bundle or an Application which contains a sizeable amount of localised content. This would go a long way towards automatically localising your newest product - but you can't find the original glossaries and incremental localisation just won't work in this case.

Dictionary Maker can help

Drop a localised bundle on Dictionary Maker and it will produce a TMX dictionary containing all the translations in the original bundle.

You can then use the dictionaries with LocFactory Editor to reduce some of the repetitive sections of your work.

TMX is an XML based Open Standard and is supported by the majority of top Translation-Memory tools.