Security, Payment gateway and other B2C related

[Andy]

Hi,

I'm currently developing my B2C application using ASP.NET. I have several
questions regarding planning this application:

In my application, I'll use my own shopping cart (developed totally in
ASP.NET / MS SQL Server for the backend).
I'm planning to accepting online payment using major credit cards
(Visa/Mastercard), and for that matter I'm currently considering to use
service from ikobo.com.
Even though this payment gateway suggesting to use their shopping cart, I'll
still use my own shopping cart. And, let this gateway to only handle the
payment verification and processing.
They're also providing ways to connect to their system variables (via form
vars) and let me just pass the total amount of the items in the cart that is
being paid along with the customer personal and CC info when the customer
click on the 'check out' button.

Well, I'm new to this so pls apologize my rather silly questions. Here're my
questions,
- Is it mandatory to use SSL to secure the confidential information
(customer's personal and CC info) during the transfer from my site to the
payment gateway secured link?
- Is there any special considerations (in regard of ASP.NET programming) in
accessing this secured folder?
- Should I use a shared SSL certificate that is shared across all the
domains that are hosted on the hosting that I use, or is it better to use a
dedicated SSL cert for my domain only?
- I'm using Windows XP Pro as my development machine. Is there any way I can
simulate this secured communications via SSL in my machine? I tried it
before but it requested to get a live cert.
- Anyone here ever heard of ikobo.com's reputation?

I'll appreciate any comments and suggestions.

Many thanks in advance,
andy