You can also specify baselines with .bes files. This is the schema:

Baselines have the following fields in common with Fixlets and tasks:
<Title> xs:normalizedString </Title> [1]
<Description> xs:string </Description> [1]
<Relevance> RelevanceString </Relevance> [0..*]
<GroupRelevance> ... </GroupRelevance> [0..1]
<Category> xs:normalizedString </Category> [0..1]
<WizardData> ... </WizardData> [0..1]
<DownloadSize> xs:nonNegativeInteger </DownloadSize> [0..1]
<Source> xs:normalizedString </Source> [0..1]
<SourceID> xs:normalizedString </SourceID> [0..1]
<SourceReleaseDate> NonNegativeDate </SourceReleaseDate> [0..1]
<SourceSeverity> xs:normalizedString </SourceSeverity> [0..1]
<CVENames> xs:normalizedString </CVENames> [0..1]
<SANSID> xs:normalizedString </SANSID> [0..1]
<MIMEField> ... </MIMEField> [0..*]

Baselines are also composed of a collection of named baseline component
groups, which contain baseline components:
<BaselineComponentCollection> [1]
    <BaselineComponentGroup Name="xs:normalizedString [0..1]"> [0..*]
            Name="xs:normalizedString [0..1]"
                TheNameattribute corresponds to the content ID
                of the action, which is a short identifier for the
                component that is used to match it up with a
                particular action of the source Fixlet/task/baseline
                of the component.
            ActionName="xs:normalizedString [0..1]"
                TheActionNameattribute is a longer description
                of the action shown on theComponentstab of the
                baseline document.
            IncludeInRelevance="xs:boolean [0..1]"
                If true, then the relevance of the component will be
                included in the relevance for the baseline. If false,
                then the baseline will be relevant regardless of
                whether this component is relevant; the individual
                component will still not be executed if it is not
            SourceSiteURL="xs:anyURI [0..1]"
                The gather site URL for the source Fixlet/task/
                baseline that this component comes from.
            SourceID="xs:nonNegativeInteger [0..1]"
                The ID of the Fixlet/task/baseline that this
                component comes from.
            > [0..*]
            <Relevance> RelevanceString </Relevance> [1]
                This component will be executed only on computers
                for which the relevance clause evaluates to true.
            <ActionScript> ActionScript </ActionScript> [1]
            <SuccessCriteria> ActionSuccessCriteria
            </SuccessCriteria> [0..1]
<Settings> ActionSettings </Settings> [0..1]
<SettingsLocks> ActionSettingsLocks </SettingsLocks> [0..1]