Areca Backup
You can use regular expressions to include / exclude source files in your backups.

Regular expressions quick reference :

Here is a listing of the most popular regular expression patterns.
Rule Syntax
Exactly one occurence of x x
At least one occurence of x x+
0 or many occurences of x x*
0 or 1 occurence of x x?
Escape character \
Any single character .
One character in a predefined set [list-of-characters] ... examples : [ABCD], [012345789]
One character in a character range [character1-character2] ... examples : [0-9], [a-zA-Z] ...
Any character except those contained in a predefined set [^list-of-characters] ... examples : [^ABCD], [^0-9]
Tab \t
New line \n
Carriage return \r
Beginning of the line ^
End of the line $

Examples :

Example Syntax
All filenames ending with ".html" ^.*\.html$
All filenames containing "client" ^.*client.*$

Additional help can be found on Areca's regular expressions wiki