Štefan Füle, the Czech commissioner for enlargement, Andris Piebalgs, his Latvian colleague responsible for development, and Kristalina Georgieva, the Bulgarian commissioner for humanitarian aid, will all assist Ashton, a Commission official said.
Catherine Ashton has endured attacks from several quarters, including French ministers, for not flying the EU flag at hotspots such as earthquake-hit Haiti or being unable to attend European gatherings.
But Commission representatives said the situation was going to change, as the EU's first-ever High Representative for Foreign and Security Policy, who is also commissioner for external relations, will now be able to use colleagues as deputies.
"I wish we had dealt with the issue of deputies at the intergovernmental conference [laying the ground for the Lisbon Treaty], but here we are," said one Commission official, who asked not to be named.
"In a European Union of 27 countries, she - or anybody else - will always be attacked for being here and not somewhere else," a diplomat told EurActiv.
Asterisks fill Lisbon Treaty void
The Lisbon Treaty, which entered into force in December last year, does not provide any deputies for the EU's foreign policy chief. However, when European Commission President José Manuel Barroso first disclosed his new team, asterisks were marked against the names of three commissioners to indicate that they would work in "close cooperation" with Ashton.
"There are three commissioners in President Barroso's college of commissioners who work in a cluster with the High Representative, and in certain circumstances they can do certain things when she is not able to do them," the Commission representative said.
The official described Füle, Piebalgs and Georgieva as "cluster commissioners" who would sometimes help Ashton be in "more than three places at a time" and who "can do things on her behalf in certain circumstances".
National ministers also 'useable' for carrying EU message
By the same token, national ministers from the 27-member bloc are equally "useable," on the basis of a pre-agreed mandate, to carry the EU's message, the official continued.
Spanish Foreign Minister Miguel Angel Moratinos, for instance, is widely acknowledged as a Middle East expert, while Sweden's Carl Bildt has extensive expertise in Western Balkan troubleshooting.
However, the official admitted that the procedures for working out such "deputising" were not yet clear. "We will have to see how deputising will go on in practice," he said.
A deputy inside the EU External Action Service?
In addition, Ashton could use a deputy from the ranks of the upcoming European External Action Service (EEAS), the official said. But he suggested that this role would be of lesser political importance.
Large EU countries such as France and Germany are struggling to place their diplomats in key positions in the EEAS, including the open position of secretary-general and the two deputy secretary-general jobs.
But according to sources, what those countries are seeking is influence in the EEAS kitchen rather than political visibility. The Commission official explained that no matter who becomes the most important EEAS official under Ashton, he or she could not "deputise" in a political manner but rather in a functional one.
"So we have three sources for HR deputies, two as alternatives rather than deputies, because this triple-hatted structure is rather a rare commodity," the official said, making it clear that only the three commissioners could act as real deputies.
