As is the case with any cookie cutter build, there isn't much discussion of skills not native to the build. But that's OK, that's what we variantmeisters are for.
Anyway, short answer is no. Conviction affects only the three elemental resistances: fire, cold, and lightning. Blessed Hammer isn't any of those three.
The offensive & support paladin you're thinking of can still be done, however! You'll just have to go with either Fist of the Heavens/Conviction or Vengeance/Conviction. A second option is Conviction with a high elemental damage weapon (Lightsaber or Kuko Shakaku perhaps). A third option is to simply hybridize any paladin build of your choice with 20 points of Conviction, which has no synergies.
Vengeance/Conviction is a particularly underrated support build, one I'd love to try someday. Vengeance's synergies provide you (and potentially the whole party) with big fat resistances and boosted max resistances to boot. Resistance auras provide a viable Plan B whenever your party has less of a "need to kill faster" problem and more of a "need not to die" problem.
Don't forget a point in the pseudo-offensive aura Meditation for between-battle mana recovery. Meditation will encourage conservative casters (Freezing Arrow amazons, Lightning trapsins, etc.) to pump out serious damage once Conviction kicks back in. And, oh yeah, with Fist of the Heavens or Vengeance, you need the mana, too.
Also remember that Conviction greatly improves the accuracy of attacks against affected monsters; physical attackers in your party can see their accuracy go from as low as 60% or 70% to the maximum of 95% against Convicted monsters! So don't be afraid to keep the Conviction going even in a non-casting party.