The mod that looked a lot like Diana (Alina Vacariu also in certain poses) is Andrea Krakhecke, a Brazilian who also appears in Elle Spain now and then... 
Kasia Smutniak confused me only once, but it was because they styled her to look like Diana, here: 
 
(Admin, it's my site, it's OK to hotlink to myself - I think...) 
Note the same Diana pose, in this Rocco ad (Wendy D in the background) 
Diana Rocco ad 
and I had that look embedded in my brain from back in 98... 
Diana pic from Nice, France