Thank you for your reply. Actually, I'm making a template file, so it's neccessary to keep it editable in EPS so other vector program can also edit it. I know it's really inconvenient, but it's the requirement so I'm really looking for a solution to this. And yes by "EPS 10" I'm referring to Illustrator 10 EPS.
Any answer are welcomed and helpful to me so I'd mark helpful to answers. Thank you
It's a common misconception.
Every drawing program has its own proprietary constructs understood by its particular user interface. For example, a text-on-a-path object built in FreeHand or Draw is not exactly the same thing as a pathType object in Illustrator. They may be similar and used for similar purposes, but are independently-developed. That's why various programs have import/export filters: For example, you can "open" an Illustrator file with FreeHand (and until CS6, could "open" a FreeHand file with Illustrator), but what's really going on is, an import filter is translating the other program's constructs into those that are native to the receiving program, with varying degrees of success, because (for one reason) the programs involved often simply don't have 100% corresponding capabilities.
Data-exchange formats, like EPS, are largely intended to serve as just that: a format through which various programs can exchange data. This is largely accomplished by, upon export, simplifying the application-specific proprietary constructs into more basic or more generic constructs that other programs can be expected to understand, according to the published exchange format standards.
So when you export to EPS, application-specific constructs get "dumbed-down" to a "lowest common denominator" set of objects (much as they are when you save to PDF). So you can't expect something that you export to EPS to contain all the application-specific behaviors and features when you re-open it, even if you re-open it in the same program from which you exported it. The very act of exporting it has broken it down into more basic objects.
Well...except that exporting type on a Path from current Illustrator to a Version 10 AI PDF doesn't work either. And exporting type on a path to Illustrator CS AI EPS does work. (Where "work" is "survives a round trip as type on a path.")
My memory is hazy, but I thought Type on a Path was introduced in Version 5 or so. Certainly it's got to have been there since Version 10, since Googling finds a discussion of it in "Illustrator 10 for Dummies."
So I think what's actually going here is that modern Illustrator's export filter doesn't know how to write path type into the Version 10 AI and EPS formats, presumably because there were some internal changes and this degree of compatibility was not preserved.
This doesn't help vectorjohn, though.