How to design a Viper 115 XS Buck-Boost converter?

Hi,

I´m designing a negative topology triac control circuit , so i need a non isolated buck-boost topology as shown in the figure 39 of the Viper 11 datasheet.

The problem comes when i hadnt been able to find any documents regarding how to do it in the stm documentation, there is the e Design suite for a typical Buck converter but if my memories of power electronics are right the Inductances , capacitor values and everything are completely different.

So, there is any guideline o document regarding how to do it?