Outlook 2007 / 2013 not rendering CSS font-family declarations - html-email

Question

I'm testing an email design with Litmus and for the life of me I cannot get my fonts to be properly set in Outlook 2007 / 2010 / 2013. Every single HTML / CSS trick / hack continues to render in Times New Roman:
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I'm mostly using simple tables for layout, so all content is ultimately inside a TD element.
Here are the various techniques I've tried to set the font.
My STYLE declaration: Have tried this in both the HEAD and BODY tags & neither works.
<style>
#font-face {
font-family: proxima-nova;
src: url('assets/ProximaNova-Reg.otf');
}
#font-face {
font-family: proxima-nova-blk;
src: url('http://assets/ProximaNova-Black.otf');
}
body *, td, p, li {
font-family: font-family:proxima-nova,'Proxima Nova Regular','Proxima Nova',verdana,sans-serif;
}
</style>
CSS STYLE attribute set on TD elements:
<td style="font-family:proxima-nova,'Proxima Nova Regular','Proxima Nova',verdana,sans-serif; color:#FFFFFF; font-weight:300;font-size:18px;">
FONT tag with both FACE and STYLE attributes set:
<font face="proxima-nova,Proxima Nova Regular,Proxima Nova,verdana,sans-serif"
style="font-size:28px;
font-family:proxima-nova,'Proxima Nova Regular','Proxima Nova',verdana,sans-serif;">
Inline CSS STYLE attributes on all inner text elements (P, LI, A):
I am COMPLETELY baffled. On all other relevant clients everything is working as well as can be expected (i.e. fonts are rendering as I'd expect given various bugs & rendering weirdnesses), including iOS, Gmail, Outlook 2003 / Express, etc.:

Answer 1

I traced the issue to my STYLE declaration, which uses the #font-face to pull in a custom font file for supporting clients (i.e. Apple). Apparently, something about this use of the #font-face declaration breaks in Outlook 2007 - 20013.
<style>
#font-face {
font-family: proxima-nova;
src: url('http://assets/ProximaNova-Reg.otf');
}
#font-face {
font-family: proxima-nova-blk;
src: url('http://assets/ProximaNova-Black.otf');
}
</style>
I needed to get MS Outlook to ignore this STYLE tag, so I wrapped the entire block with the [if !mso] tag:
<!--[if !mso]><!-->
<style>
#font-face {
...
}
</style>
<!--<![endif]-->
Wow, that was driving me crazy.

Answer 2

I've tried your solution with the [if !mso] tag, but for some reason it wouldn't work. I eventually found a different solution:
You can use the font-tag with the face-attribute to force the right fallback-font in clients like Outlook 2007/2010/2013. For example:
<td style="color:#FFFFFF; font-weight:300;font-size:18px;">
<font face="proxima-nova,'Proxima Nova Regular','Proxima Nova',verdana,sans-serif"
</td>
I tested this in Litmus and in Outlook 2007/2010/2013 it would fallback to Verdana and in clients who do support the custom font, it would show proxima-nova.
I hope this helps.