Well, i found a way to mount a network shared folder into my android device using Xamarin (C#), just as Mount Manager and CIFS manager does;
You need root permissions to make it work because it's a unix command and need especial permisions.
The code it's as simple as the next:
Java.Lang.Runtime proc = Java.Lang.Runtime.GetRuntime();
proc.Exec(new String[] {"su", "-c", "mount -t cifs -o username=USER, " +
"password=YOURPASS //xxx.xxx.xxx.xxx/SharedFolder /mnt/sdcard/MountPoint"});
In the code above, replace USER with the user name and YOURPASS with the password to access the network folder.
Replace xxx.xxx.xxx.xxx with the server IP.
Replace MountPoint with the name of the folder where you want to mount the network folder, you can also replace sdcard with another directory and even the /mnt with another one, but it's most common to mount into the sdcard, this way any app that scans your sd will see the network files as they're on the sd.