Binding not working when returning to same page

Question

Hi, Im developing a portlet that access some data from MYSQL.
I have a simple page with several textfields, all with bindings to a javabean object that is a property of SessionBean1 bean, so it is a Session Scope bean.
In that page I put some buttons like next, prior, etc. to navigate between all registers of my DB. I added some code to event button like this:
public String bnext_action() {
// get sessionbean
SessionBean1 SBean1 = (SessionBean1)getBean("SessionBean1");
// navigate to next register in database
// ProdBean is my property bean that get values from database
// bindings are like this : text="#{SessionBean1.prodBean.codigo}
SBean1.getProdBean().GetNextReg(SBean1.getModuloIdx());
// set current register index
SBean1.setModuloIdx(SBean1.getProdBean().getIndex());
return null;
The problem is that when I get next register of database, bindings are not reflecting new values, always holding first values. I tried to force things by setting values in pre-rendering face manually with setText method of textfields but nothing happens.
As Im a newbie in Java yet I really don't undestand this, I have readed all JSF life cycle documention and portlet life cycle docs but couldn't find an answer. Why binding is not working?

Answer 1

Thanks for this.  Unfortunately now I have tried with Standard actions the links do not work at all.  The links provided were created with spaces so contained within the links are lots of '%20'. e.g. :
PCI%20DSS/UWE%20PCI-DSS%20Quick%20Reference%20guide.pdf
for some reason when creating the links with standard actions, when the project is published the links have changed to contain 25s  e.g.
PCI%2520DSS/UWE%2520PCI-DSS%2520Quick%2520Reference%2520guide.pdf
no idea why this is happening.