Valve wants the Xbox Live Arcade version of upcoming shooter Counter-Strike: Global Offensive to feature Steamworks integration.
But it faces a tough job convincing Microsoft to let it do so.
"We certainly can deliver a lot of value to customers to the degree to which we have those capabilities," Valve boss Gabe Newell told Eurogamer.
"The PS3, obviously we made a lot more progress with that. The PS3 customers of Portal 2 are going to start to see the benefits of that with Portal 2 DLC coming out in September. So we'd really like to be able to do that for Xbox customers as well."
The PS3 version of Portal 2 features a number of exclusive features as a result of Steamworks integration, including cross-platform play with the PC version.
There's also cross-platform chat, Steam Achievements (earned in synch with Trophies), player profiles and game invites. You can even play Portal 2 on a PC or Mac - Valve grants a free PC/Mac Steam edition of the game to PS3 gamers.
Xbox Live, however, remains a closed platform, with Microsoft employing strict guidelines on what publishers can and cannot do.
"The main thing is having Microsoft get comfortable with it and let us do it," Newell said of the challenges Valve faces bringing Steamworks to Xbox.
"Right now, there's a huge amount of updates and free content we've been able to deliver to people who have The Orange Box that we haven't been able to deliver to the Xbox because of the restrictions that have been placed on us on Xbox Live.
"We'd love to see those relaxed. Other developers on the PS3 are starting to benefit from Sony's more open approach. Hopefully that will help Microsoft see that's a good strategy for making customers happy, that the barbarians won't tear down the walls of Xbox and turn it into some chaotic wasteland."
One game making use of Sony's more relaxed policy is Dust 514, from Eve Online developer CCP.
"Let's just say that with Sony at least they have policies that allow us to build the game the way we want," CCP CTO Halldor Fannar said during an E3 presentation attended by Eurogamer in June. "That is one of the reasons why we've gone with PSN."
Valve isn't the first MMO developer to find Xbox Live troublesome.
Last year Final Fantasy XIV Online creator and director Hiromichi Tanaka told Eurogamer that a "closed" Xbox Live blocked the game from appearing on Xbox 360.
"The main reason why we couldn't go with Xbox 360 was the Xbox Live system," he explained. "[Live is] different to the normal internet environment, so when we wanted to introduce this game in the same environment as Windows PC it had to be PS3, so that was our choice.
"Microsoft has a different point of view: they want to have a closed environment for Xbox Live. We're still talking to... We couldn't come to an agreement on Xbox Live."
MMO developer Cryptic chucked in the towel on an Xbox 360 version of Champions Online in early 2010. Producer Craig Zinkievich told Eurogamer he was frustrated with the business side of getting an MMO on Xbox Live; the game itself, he said, ran just fine.
Sony, however, seems more open to the idea of allowing MMO developers to play by their own rules on the Network.
"Sony allows us to use our systems," Fannar explained. "Microsoft has Xbox Live. They're very strict on that. There are a lot of issues we run into. It may be a basic thing people don't realise, but with Dust and Eve on Sony's network, we can allow them to chat together. Voice chat, text chat, that's all one world.
"One of the reasons for the partnership with Sony is because they're opening up new ways to do these things. We're going to be managing most of it. We're using PlayStation just for credentials, stuff like that. Then it's all our stuff.
"With our agreement with Sony they seem to be fine with our three month expansion cycle. They've been looking at the MMO space for a while, trying to understand why something like that hasn't still happened on the console. They're coming to terms with it. There are certain things they have to relax just to allow these things to function."
Still, there appears to be hope for Xbox 360 owners - a report in June claimed free-to-play games were coming to the console and that Microsoft was talking with developers to discuss free-to-play game deals.
And last month Hi-Rez Studios boss Todd Harris, who is making Tribes: Ascend, told Eurogamer free-to-play games supported by micro-transactions on Xbox 360 were "inevitable".
Valve is yet to decide how to monetise CS: GO - indeed it may end up free to play, as its other shooter, Team Fortress 2, is.