Cannot deploy-file to sftp using another username/password

I'm trying to copy one artifact to my shared repository.
I have the original .pom and .jar files downloaded locally from an external repository.
My settings file has:

<server>
<id>jquantlib-external_free</id>
<username>continuum</username>
<password>secret</password>
</server>

My pom.xml has:

<repository>
<id>jquantlib-external_free</id>
<name>JQuantLib External Free Repository</name>
<url>sftp://ftp.jquantlib.org/maven2/repos/external_free</url>
<layout>default</layout>
<uniqueVersion>false</uniqueVersion>
</repository>

These are the test cases and results:

1) initial trial according to documentation:

mvn deploy:deploy-file -DpomFile=joda-primitives-0.6.pom -Durl=sftp://ftp.jquantlib.org/maven2/repos/external_free -DrepositoryId=jquantlib-external_free -Dfile=lib/joda-primitives-0.6.jar -X -e

It does ask not any authentication information but seems it's not picking up anything from settings.xml, otherwise it would connect properly.

2) Trying to specify the username/password in the command line:

mvn deploy:deploy-file -DpomFile=joda-primitives-0.6.pom -Durl=sftp://continuum:secret@ftp.jquantlib.org/maven2/repos/external_free -DrepositoryId=jquantlib-external_free -Dfile=lib/joda-primitives-0.6.jar -X -e

Authentication information is simply ignored.

3) Trying to removed 'repositoryId'

mvn deploy:deploy-file -DpomFile=joda-primitives-0.6.pom -Durl=sftp://continuum:secret@ftp.jquantlib.org/maven2/repos/external_free -Dfile=lib/joda-primitives-0.6.jar -X -e

Authentication information is simply ignored.
Asks my password (and not the password of account continuum):
Password for rgomes@ftp.jquantlib.org:

4) back to the initial test and the stack trace

mvn deploy:deploy-file -DpomFile=joda-primitives-0.6.pom -Durl=sftp://ftp.jquantlib.org/maven2/repos/external_free -DrepositoryId=jquantlib-external_free -Dfile=lib/joda-primitives-0.6.jar -X -e

(logfile attached)

Thanks a lot

Richard Gomes