Adding a banner under the nav bar

[Macsee]

I wish to add an SSI that acts as a 90 pixel high space extending the whole width of the page. I would like it to appear just under the nav bar on all pages of the blog and forum - every location on the site.

Any suggestion of which template I would add the SSI <include> code?

[LouiseWilson]

tried adding it in the Ad Location Templates > ad_navbar_below ?

however I believe the templates do not support php or includes