As I understand it for the csv file to retain the potential for its target database to display 'as formatted' (and assuming that the target will support that form of display) the format control characters all have to be exported surrounded by double quotation marks. However that alone dos not guarantee that the text will display as per the original layout once viewed from the new host application.
[URL="http://www.monarchforums.com/showthread.php?t=1608&highlight=text+format&page=2"]Here[/URL] you can find a thread that discusses (mostly) the inverse of your problem (sort of) after a point update in version 6. (However the export in this case seems to be direct to Excel - I rembered the case but don't remember the specifics clearly beyond what is described in the thread.)
One of the problems to consider is that whilst a csv file may offer the facility (according to Wikipedia) to pass embedded format codes for line feeds and carriage returns the receiving application may not use them. Indeed for space saving purposes (historically) character reduction tended to be favoured and that would probably still be the safest assumption to use even today for a generic output like a csv file.
I don't recall exactly what V5 does in that area. Are the format controls dropped in the CSV export or are they there but not clearly defined (no double quotes) for example? If the latter it may be possible to post process the file, using something like the MSRP.exe utility, to add the quote marks. If the former it may be possible to add the quote marked formats in Monarch via a calculated field - but you will only have 254 characters to play with I think. It would also be worth checking that the target applications for the csv file can make use of the format codes if they get them. (You may already have done that of course...)
I no longer have ready access to a V5 installation so I can't help much more with checking and testing but I hope this helps you work out what your options are.