How to overwrite existing MT translations in target segment when run MT plugin

Hi,

Hope I raise the question in right place.

I designed a customized MT plugin refer to the sdk of plugin, it works well.

But I want to know is it possible to overwrite existing MT in target segments when call another MT engine by the plugin. I mean I receive one file which has contains MT in target segments, but I want to apply MT again with my own MT engine to overwrite existing MT translations in this file.

I tried serval times, but it seems existing MT can't be overwritten.  Any idea is much appreciate.

I know if I clear all existing MT first, then apply MT by my own engine, it works, but I want to add option my plugin (Overwrite existing MT) to control this instead of clear them manually.

Thanks in advance.

Luhao