Personalization to change a flexfield value, when inactivate Asset.

In Oracle EAm, in the Asset Numbers Form, I need to make a personalization in order to change a value in a flexfield, after someone executes the "De-activates Asset Number" Function.

But i have a problem, the personalization does make the change in the flexfield, but then the "De-activates Asset Number"  doesn't work, i can save the changes, but when i look again for that asset number, the "Active" check is "Checked" and it should be "Unchecked".

Is there any other way to make this personalization work?