Arduino as USB to serial converter and use for ImageJ?

Hello, everyone.
I must first state that i'm not a electronics major. and i have nearly none knowledge on circuits and programming.
but as a current master student. in our lab, we have to construct a microscope system.

we have a special ordered motorized stage which controls x y and z(knob). and it is basically controlled by sending
strings through RS232 DB-9 serial port.

Our setup will be that a laptop(without RS232) needs to control a motorized stage, a magneto-operated shutter(which the board appears to be TTL), and a canon DSLR.

I was investigating the feasibility of using micro-manager to do all this.
but i found a plugin in imageJ which is called serial macro extensions.
and in the wiki page it stated that it was developed for arduino projects in the first place but should work well with all serial devices.
however i was having trouble using that plugin using a USB to serial converter cable. there would be errors.
i'm not sure whether the software is set up correctly(but i did checked) or that it's not seeing USB to serial converter. i'm seeking advices on imageJ maillist.

since we also need to control a magneto-operated shutter too.
so i was wondering if it is possible to use an arduino uno(?) to do the two.

Question1. can i make a custom DB-9 connector that can send and receive strings to the motorized stage controller? from arduino uno by connecting the pins? treating arduino board as a usb-serial converter? is this possible?
because i didn't find any post on the internet by "RS232 and Arduino"

Question 2. is it possible to use one arduino uno board to do what i want in question 1 and able to control a TTL controlling magneto-operated shutter?

because our lab is not well funded, so we bought cheaper custom hardware.
but i am not good at programming. so the device adapters for micro-manager are huge headaches to me.
but i did find arduino adapter for micromanager.
i had high hope. but i'm really not sure.

i really hope you can help me out.
thank you

I would think yes.
Use a device like this
http://www.amazon.com/IEC-USB-RS232-Serial-Converter/dp/B003U46BL0
to have RS232 connector from your Uno to the motorized device, create the strings to send out by reading the voltage on a set of potentiometers, or move a step at time using pushbutton inputs.

The TTL shutter is also doable, maybe with extra current drive added via transistor if arduino's 30-35mA is not enough.
Can be programmed to go off with button push, reading a pin to detect a voltage or some external event for example.