How to generate gradle repositories into pom.xml using gradle's maven plugin

Hi, I’m trying to generate pom.xml to upload a test project to appcenter. The project is build in gradle and I’m using maven plugin to generate pom.xml from it. In build.gradle I have some custom maven repositories and when pom.xml is generated, those repositories are not present, so if I run some mvn task it says that dependencies couln’t be found. How can I specify in createPom task the custom repos?.