Customizing the Opportunity ListColumns in other modules

[radu]

and if you replace modifiedtime with createdtime?
Target module is Opportunities, yes?
I have this fields and it works:
<field>
<label>Created Time</label>
<name>createdtime</name>
</field>
<field>
<label>Finalizat</label>
<name>cf_1265</name>
</field>

of course cf_1265 is a cf that exist in modules layout(my case Salesorder, your case Opportunities)