problem with numeric screen field....

hi,

I've gotta situation that,

In sales order we gotto determine WBS element(ps_psp_pnr) based on some conditions, if none of the condition is satisfied then the 'project definition'(prps-pspid) has to be concatenated with '.99' and displayed as WBS element.

Now the actual problem is, WBS element is of numeric character type whereas the projectdefinition(pspid)+.99 is of charcter type. So it throws me a dump. Even then, the screen field of WBS element doesnt shows any non numeric character and shows error message.

So how do i overcome this situation? Can anyone help me? Its quiet urgent.

Prompt answeres will be rewarded with points.

with regards,

praveen.