Hi suema,
The SleepEZ foundation would need a suitable bedframe underneath it so you would either need to use a steel bedframe inside your headboard and foorboard and siderails (and remove the slats on top) to support the foundation or you would need to add enough slats and good center support to your bedframe to be able to support the foundation and the mattress. If you do decide to modify your bedframe to be able to support a foundation and your mattress then some of the suggestions in post #5 here may be helpful.
There is more information about suitable support systems for a latex mattress in the foundation post here but if you decided to turn your your current bedframe into a platform bed that can be used directly under a latex mattress without a foundation to support the latex mattress directly then you would need to add enough slats (again with good center support) so that they could support the mattress directly without a foundation and to make sure that the distance between the slats was no more than 3".
Phoenix