Linker Building in scFv

Dear Rosetta Users, 

I would like to build a linker that connects the VH to the VL domain of a single-chain Fv.
The length of the linker is ~15 aa (actually I'm going to build two linkers which differs in term of length).

In the literature, I found a case in which the RosettaRemodel application was used to perform a loop closure with a glycine-serine linker between two domains.

However, the sequence of my linker is known and it must not be changed. 
I just need to build -and not design- the linker.

I think that the Next-Generation Kinematic loop modeling is the most suitable method for my task.

Does anyone have any advice or experienced a similar case? 
 

Thanks in advance!
Samuele