SSO and IFrame, more details please

I have faced some projects for example intranet portal for a company or organization, and one of the modules is to make SSO with an existing application and that we will load the application within an IFrame in our page, something seems very simple, but is it that simple in the client imaginations or he will find something else at the end with the delivery, so we must make some point clear to the customer from the beginning like:

A. Points related to the SSO:
1. SSO itself
2. Sign out
3. Session expiration
4. Browse directly to the application URL

B. Point related to the Frame:
1. Frame/Iframe
2. Header
3. Welcome Message
4. Navigation



A.1. SSO itself:
A group of questions we must know here depend on the case , is it a product or the client have the source code, can we add some pages or DLLs to the application, can we use cookies, what will be the authentication type in both applications, can we encrypt/decrypt, can we use ISA to authenticate the users, can we use MOSS SSO, is there a common membership provider, and so on.

A.2. Sign out:
Is it required to sign the user out from the portal if he click on sign out in the other application, or is it required to sign him out from the application if he click on sign out from the portal? Where I’ll redirect the user in the portal if he logged out from the application?

A.3. Session expiration
How we will manage the session expiration in any of the two applications, the user may expend more time on the application and his session on the portal is expired and vies versa. Is it required to keep the session live while the user is browsing the other application?

A.4. Browse directly to the application URL
What if the user type the URL of the application while he is already signed in on the portal, is it required to authenticate him on the application also or not.

B1. Frame/Iframe:
What about the look of the page, is it okay to have many scroll bars in the same page, is the size of the frame is sufficient to display the application screens? What about the color schema of the application, is it okay with the portal colors? So we can ask, what is the problem with a popup/new window?

B2. Header:
If the application has his own header, so you will have two headers in the same page which mean more lost space, and may be two logos.

B.4. Navigation:
The same here for the navigation, if the application has its own navigation, so we will have extra navigation and extra lost space, and for the usability it is not a good practice.

B3. Welcome Message:
In case the two applications have separated membership providers or user profiles, you will see in the same page for example, Welcome omourad and Welcome Osama Mourad, is it okay? And the user may sign in with another user in the application, you will see in the same page for example Welcome omourad and Welcome Ahmed El Said.