Modified file mode when accessing source over a samba share

First let me say what a great tool SourceTree is. I use it daily.

I have a project that I need to run from an Ubuntu based VM. I have created a samba share so that I can get at the files on my windows workstation.

Unfortunately, even though git on the Ubuntu machine tells me that tells me that all the files are on SorceTree (or git on Windows) is telling me that the files have been modified because the mode has changed from 755 to 644. It says 'Modified File Mode 100755 -> 100644'.

Is this a SourceTree problem, a git problem or a Ubuntu Samba problem. Is there any way that I can tell SourceTree to ignore the file mode?

Chris