[Samba] mostly unix clients + subversion

[Mathijs Kwik]

Hello,

I'm working at a web-development company and I wanted to use samba as
a central fileserver.
Most client-computers use linux and osX, but there are some windows
PC's on the network also.

We use subversion as a central repository and (until now) all
developers had to checkout their working copies to their own machines.

Since we mostly use Ruby on Rails for development, this means every
developer has to have a local ruby environment with rails and plugins
and stuff.
Because all platforms have different packages for those things, this
sometimes creates problems.

So I want to give everybody a home-directory on samba, to which they
can checkout the repository. This way everybody can run their own
rails-instance on the server (started up via ssh for example) but
still use their own local text/html-editor and subversion GUI clients
that they are used to, since all 3 OS'es can mount samba-shares as
native filesystems.

Now, my question(s):

Is it possible for samba to keep unix file permissions unchanged to
unix-clients (linux/osX) ?
I found that samba removes the executable bit from files (scripts),
which is very unpleasant.
I am using these settings for the share:
create mask = 0777
security mask = 0777
force security mode = 0000
directory mask = 0777
directory security mask = 0777
force directory security mode = 0000

(only if question 1 can be confirmed)
Are there any special settings required to make subversion-working
copies be exported correctly through samba? Right now I'm experiencing
lots of problems just copying them from a mounted samba share to my
local (linux) machine and even more the other way around, so I didn't
even try to use a subversion-client on them.

tnx in advance for any help.

Greetings,
Mathijs