SVG hidden construction

Hallo,

I work with Pvz files in Creo Illustrate 9.0.

The concerned parts that do show in Creo Illustrate are the "Model Construction Geometry Surfaces". 

The Pvz file does contain them and is not the problem. 

These parts do not however show in the Svg export. 

These "Model Construction Geometry Surfaces" concern parts we buy, for example a gearbox or an air filter. 

These parts are used in our Cad models, next to the parts we model ourselves. 

I am working on a parts catalogue and I need all parts to show in the Svg (an exploded view). 

how can I make that happen? 
thank you in advance