I do not think you will be able to do that .....There is a content root parameter which tells Form Server where your content is located ...normally relative links are used from that location.
Ok, so if use forms with fragments necessarily these (XDP and fragments) must be in the repository of LC?
If the XDP (include fragments) is NOT in the LC repository where LC Forms would we look for fragments?
I have not seen any place where these issues are explained in detail. Where I can get more information about this issue?
The fragment location woudl be relative to the location that the form was loaded.
Regarding the docs, if you look at the Forms Server docs it woudl describe the purpose of the Content Root URI parameter not neccesarily all that it can be used for. Note that the same thing woudl apply for any other links (like images) that woudl be on the form.
Here is the writeup that comes from inside of workbench:
The URI or an absolute reference to the location from which form resources are retrieved. When Content Root URI refers to a repository location then it should conform to "repository://authority/resource location". For example if a resource "resourceName" is present and if Content Root URI is set as "repository:/a/b/" then authority is null and resource path is resolved as "/a/b/resourceName", and if Content Root URI is set as repository:///a/b/ then authority is empty and resource path is "/a/b/resourceName", and if resource is "/resourceName" and Content Root URI is set as "repository://a/b" then authority is "a" and resource path is /b/resourceName. Type: string.