"If everything goes okay, then we will expand the programme (in) the kingdom," he said on Tuesday.
Ismail said the company has been quiet about the move due to the sensitivity of the issue.
A conservative Islamic educator has already called for a boycott of Panda due to the mixing, but it is not yet clear whether that has had any impact.
Operating more than 100 retail stores across the country, the United Azizia Panda Co, owned by publicly listed foods giant Savola, already employs women sales clerks in its hypermarket in Dubai in the United Arab Emirates.
But inside Saudi Arabia, Islamic conservatives have for decades enforced a prohibition against unrelated men and women mixing in the workplace.
The result is that nearly all retail sales are conducted by men.
A Jeddah University business professor, Reem Asaad, has been campaigning since 2008 to force the labour ministry to allow women sales clerks in lingerie shops, but with little success.
The caution in the test suggests how sensitive and revolutionary the idea is, in a country that bans women from driving and forces them to cover up in shroud-like black abayas and face-covering veils when in public.
The test was permitted by the local labour office in Jeddah, the relatively progressive Saudi city where the kingdom's ultra-conservative rules on women are more loosely enforced.
Inside the HyperPanda market in the Roshan mall in a wealthy area of Jeddah, the female cashiers are sectioned off in check-out lanes "reserved for women and families."
That models Saudi restaurants, which have separate sections for men and for women and families.
Unlike their male counterparts, the new cashiers are not in Panda uniforms, instead wearing abayas and veils.
Ismail stresses that the company has mainly hired "needy" women -- those who lack other sources of income.
"We want to help them," he said.
Still, Ismail said the company plans to expand the programme nationwide, if the labour ministry gives the go-ahead.
"We are waiting for permission."
But opposition to Panda's move has already materialised.
Last week, Sheikh Yussef al-Ahmad, a professor at Riyadh's Imam University known for his strident opposition to gender mixing, called on a television programme to boycott Panda.
Ahmad said mixing was against Islamic tenets and an aspect of the westernisation of Islamic culture.